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				197	<!-- ! Licensed to the Apache Software Foundation (ASF) under one
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				213	! --><h1>Asterix: Using Functions</h1>
				214	<div class="section">
				215	<h2><a name="Table_of_Contents"></a><a name="toc" id="toc">Table of Contents</a></h2>
				216
				217	<ul>
				218
				219	<li><a href="#NumericFunctions">Numeric Functions</a></li>
				220
				221	<li><a href="#StringFunctions">String Functions</a></li>
				222
				223	<li><a href="#AggregateFunctions">Aggregate Functions</a></li>
				224
				225	<li><a href="#SpatialFunctions">Spatial Functions</a></li>
				226
				227	<li><a href="#SimilarityFunctions">Similarity Functions</a></li>
				228
				229	<li><a href="#TokenizingFunctions">Tokenizing Functions</a></li>
				230
				231	<li><a href="#TemporalFunctions">Temporal Functions</a></li>
				232
				233	<li><a href="#RecordFunctions">Record Functions</a></li>
				234
				235	<li><a href="#OtherFunctions">Other Functions</a></li>
				236	</ul>
				237	<p>Asterix provides various classes of functions to support operations on numeric, string, spatial, and temporal data. This document explains how to use these functions.</p></div>
				238	<div class="section">
				239	<h2><a name="Numeric_Functions_Back_to_TOC"></a><a name="NumericFunctions" id="NumericFunctions">Numeric Functions</a> <font size="4"><a href="#toc">[Back to TOC]</a></font></h2>
				240	<div class="section">
				241	<h3><a name="abs"></a>abs</h3>
				242
				243	<ul>
				244
				245	<li>
				246	<p>Syntax:</p>
				247
				248	<div class="source">
				249	<div class="source">
				250	<pre>abs(numeric_expression)
				251	</pre></div></div></li>
				252
				253	<li>
				254	<p>Computes the absolute value of the argument.</p></li>
				255
				256	<li>Arguments:
				257
				258	<ul>
				259
				260	<li><tt>numeric_expression</tt>: A <tt>int8</tt>/<tt>int16</tt>/<tt>int32</tt>/<tt>int64</tt>/<tt>float</tt>/<tt>double</tt> value.</li>
				261	</ul></li>
				262
				263	<li>Return Value:
				264
				265	<ul>
				266
				267	<li>The absolute value of the argument with the same type as the input argument, or <tt>null</tt> if the argument is a <tt>null</tt> value.</li>
				268	</ul></li>
				269
				270	<li>
				271	<p>Example:</p>
				272
				273	<div class="source">
				274	<div class="source">
				275	<pre>let $v1 := abs(2013)
				276	let $v2 := abs(-4036)
				277	let $v3 := abs(0)
				278	let $v4 := abs(float("-2013.5"))
				279	let $v5 := abs(double("-2013.593823748327284"))
				280	return { "v1": $v1, "v2": $v2, "v3": $v3, "v4": $v4, "v5": $v5 }
				281	</pre></div></div></li>
				282	</ul>
				283
				284	<ul>
				285
				286	<li>
				287	<p>The expected result is:</p>
				288
				289	<div class="source">
				290	<div class="source">
				291	<pre>{ "v1": 2013, "v2": 4036, "v3": 0, "v4": 2013.5f, "v5": 2013.5938237483274d }
				292	</pre></div></div></li>
				293	</ul></div>
				294	<div class="section">
				295	<h3><a name="ceiling"></a>ceiling</h3>
				296
				297	<ul>
				298
				299	<li>
				300	<p>Syntax:</p>
				301
				302	<div class="source">
				303	<div class="source">
				304	<pre>ceiling(numeric_expression)
				305	</pre></div></div></li>
				306
				307	<li>
				308	<p>Computes the smallest (closest to negative infinity) number with no fractional part that is not less than the value of the argument. If the argument is already equal to mathematical integer, then the result is the same as the argument.</p></li>
				309
				310	<li>Arguments:
				311
				312	<ul>
				313
				314	<li><tt>numeric_expression</tt>: A <tt>int8</tt>/<tt>int16</tt>/<tt>int32</tt>/<tt>int64</tt>/<tt>float</tt>/<tt>double</tt> value.</li>
				315	</ul></li>
				316
				317	<li>Return Value:
				318
				319	<ul>
				320
				321	<li>The ceiling value for the given number in the same type as the input argument, or <tt>null</tt> if the input is <tt>null</tt>.</li>
				322	</ul></li>
				323
				324	<li>
				325	<p>Example:</p>
				326
				327	<div class="source">
				328	<div class="source">
				329	<pre>let $v1 := ceiling(2013)
				330	let $v2 := ceiling(-4036)
				331	let $v3 := ceiling(0.3)
				332	let $v4 := ceiling(float("-2013.2"))
				333	let $v5 := ceiling(double("-2013.893823748327284"))
				334	return { "v1": $v1, "v2": $v2, "v3": $v3, "v4": $v4, "v5": $v5 }
				335	</pre></div></div></li>
				336	</ul>
				337
				338	<ul>
				339
				340	<li>
				341	<p>The expected result is:</p>
				342
				343	<div class="source">
				344	<div class="source">
				345	<pre>{ "v1": 2013, "v2": -4036, "v3": 1.0d, "v4": -2013.0f, "v5": -2013.0d }
				346	</pre></div></div></li>
				347	</ul></div>
				348	<div class="section">
				349	<h3><a name="floor"></a>floor</h3>
				350
				351	<ul>
				352
				353	<li>
				354	<p>Syntax:</p>
				355
				356	<div class="source">
				357	<div class="source">
				358	<pre>floor(numeric_expression)
				359	</pre></div></div></li>
				360
				361	<li>
				362	<p>Computes the largest (closest to positive infinity) number with no fractional part that is not greater than the value. If the argument is already equal to mathematical integer, then the result is the same as the argument.</p></li>
				363
				364	<li>Arguments:
				365
				366	<ul>
				367
				368	<li><tt>numeric_expression</tt>: A <tt>int8</tt>/<tt>int16</tt>/<tt>int32</tt>/<tt>int64</tt>/<tt>float</tt>/<tt>double</tt> value.</li>
				369	</ul></li>
				370
				371	<li>Return Value:
				372
				373	<ul>
				374
				375	<li>The floor value for the given number in the same type as the input argument, or <tt>null</tt> if the input is <tt>null</tt>.</li>
				376	</ul></li>
				377
				378	<li>
				379	<p>Example:</p>
				380
				381	<div class="source">
				382	<div class="source">
				383	<pre>let $v1 := floor(2013)
				384	let $v2 := floor(-4036)
				385	let $v3 := floor(0.8)
				386	let $v4 := floor(float("-2013.2"))
				387	let $v5 := floor(double("-2013.893823748327284"))
				388	return { "v1": $v1, "v2": $v2, "v3": $v3, "v4": $v4, "v5": $v5 }
				389	</pre></div></div></li>
				390	</ul>
				391
				392	<ul>
				393
				394	<li>
				395	<p>The expected result is:</p>
				396
				397	<div class="source">
				398	<div class="source">
				399	<pre>{ "v1": 2013, "v2": -4036, "v3": 0.0d, "v4": -2014.0f, "v5": -2014.0d }
				400	</pre></div></div></li>
				401	</ul></div>
				402	<div class="section">
				403	<h3><a name="round"></a>round</h3>
				404
				405	<ul>
				406
				407	<li>
				408	<p>Syntax:</p>
				409
				410	<div class="source">
				411	<div class="source">
				412	<pre>round(numeric_expression)
				413	</pre></div></div></li>
				414
				415	<li>
				416	<p>Computes the number with no fractional part that is closest (and also closest to positive infinity) to the argument.</p></li>
				417
				418	<li>Arguments:
				419
				420	<ul>
				421
				422	<li><tt>numeric_expression</tt>: A <tt>int8</tt>/<tt>int16</tt>/<tt>int32</tt>/<tt>int64</tt>/<tt>float</tt>/<tt>double</tt> value.</li>
				423	</ul></li>
				424
				425	<li>Return Value:
				426
				427	<ul>
				428
				429	<li>The rounded value for the given number in the same type as the input argument, or <tt>null</tt> if the input is <tt>null</tt>.</li>
				430	</ul></li>
				431
				432	<li>
				433	<p>Example:</p>
				434
				435	<div class="source">
				436	<div class="source">
				437	<pre>let $v1 := round(2013)
				438	let $v2 := round(-4036)
				439	let $v3 := round(0.8)
				440	let $v4 := round(float("-2013.256"))
				441	let $v5 := round(double("-2013.893823748327284"))
				442	return { "v1": $v1, "v2": $v2, "v3": $v3, "v4": $v4, "v5": $v5 }
				443	</pre></div></div></li>
				444	</ul>
				445
				446	<ul>
				447
				448	<li>
				449	<p>The expected result is:</p>
				450
				451	<div class="source">
				452	<div class="source">
				453	<pre>{ "v1": 2013, "v2": -4036, "v3": 1.0d, "v4": -2013.0f, "v5": -2014.0d }
				454	</pre></div></div></li>
				455	</ul></div>
				456	<div class="section">
				457	<h3><a name="round-half-to-even"></a>round-half-to-even</h3>
				458
				459	<ul>
				460
				461	<li>
				462	<p>Syntax:</p>
				463
				464	<div class="source">
				465	<div class="source">
				466	<pre>round-half-to-even(numeric_expression, [precision])
				467	</pre></div></div></li>
				468
				469	<li>
				470	<p>Computes the closest numeric value to <tt>numeric_expression</tt> that is a multiple of ten to the power of minus <tt>precision</tt>. <tt>precision</tt> is optional and by default value <tt>0</tt> is used.</p></li>
				471
				472	<li>Arguments:
				473
				474	<ul>
				475
				476	<li><tt>numeric_expression</tt>: A <tt>int8</tt>/<tt>int16</tt>/<tt>int32</tt>/<tt>int64</tt>/<tt>float</tt>/<tt>double</tt> value.</li>
				477
				478	<li><tt>precision</tt>: An optional integer field representing the number of digits in the fraction of the the result</li>
				479	</ul></li>
				480
				481	<li>Return Value:
				482
				483	<ul>
				484
				485	<li>The rounded value for the given number in the same type as the input argument, or <tt>null</tt> if the input is <tt>null</tt>.</li>
				486	</ul></li>
				487
				488	<li>
				489	<p>Example:</p>
				490
				491	<div class="source">
				492	<div class="source">
				493	<pre>let $v1 := round-half-to-even(2013)
				494	let $v2 := round-half-to-even(-4036)
				495	let $v3 := round-half-to-even(0.8)
				496	let $v4 := round-half-to-even(float("-2013.256"))
				497	let $v5 := round-half-to-even(double("-2013.893823748327284"))
				498	let $v6 := round-half-to-even(double("-2013.893823748327284"), 2)
				499	let $v7 := round-half-to-even(2013, 4)
				500	let $v8 := round-half-to-even(float("-2013.256"), 5)
				501	return { "v1": $v1, "v2": $v2, "v3": $v3, "v4": $v4, "v5": $v5, "v6": $v6, "v7": $v7, "v8": $v8 }
				502	</pre></div></div></li>
				503	</ul>
				504
				505	<ul>
				506
				507	<li>
				508	<p>The expected result is:</p>
				509
				510	<div class="source">
				511	<div class="source">
				512	<pre>{ "v1": 2013, "v2": -4036, "v3": 1.0d, "v4": -2013.0f, "v5": -2014.0d, "v6": -2013.89d, "v7": 2013, "v8": -2013.256f }
				513	</pre></div></div></li>
				514	</ul></div></div>
				515	<div class="section">
				516	<h2><a name="String_Functions_Back_to_TOC"></a><a name="StringFunctions" id="StringFunctions">String Functions</a> <font size="4"><a href="#toc">[Back to TOC]</a></font></h2>
				517	<div class="section">
				518	<h3><a name="string-to-codepoint"></a>string-to-codepoint</h3>
				519
				520	<ul>
				521
				522	<li>
				523	<p>Syntax:</p>
				524
				525	<div class="source">
				526	<div class="source">
				527	<pre>string-to-codepoint(string_expression)
				528	</pre></div></div></li>
				529
				530	<li>
				531	<p>Converts the string <tt>string_expression</tt> to its code-based representation.</p></li>
				532
				533	<li>Arguments:
				534
				535	<ul>
				536
				537	<li><tt>string_expression</tt> : A <tt>string</tt> that will be converted.</li>
				538	</ul></li>
				539
				540	<li>Return Value:
				541
				542	<ul>
				543
				544	<li>An <tt>OrderedList</tt> of the code points for the string <tt>string_expression</tt>.</li>
				545	</ul></li>
				546	</ul></div>
				547	<div class="section">
				548	<h3><a name="codepoint-to-string"></a>codepoint-to-string</h3>
				549
				550	<ul>
				551
				552	<li>
				553	<p>Syntax:</p>
				554
				555	<div class="source">
				556	<div class="source">
				557	<pre>codepoint-to-string(list_expression)
				558	</pre></div></div></li>
				559
				560	<li>
				561	<p>Converts the ordered code-based representation <tt>list_expression</tt> to the corresponding string.</p></li>
				562
				563	<li>Arguments:
				564
				565	<ul>
				566
				567	<li><tt>list_expression</tt> : An <tt>OrderedList</tt> of code-points.</li>
				568	</ul></li>
				569
				570	<li>Return Value:
				571
				572	<ul>
				573
				574	<li>A <tt>string</tt> representation of <tt>list_expression</tt>.</li>
				575	</ul></li>
				576
				577	<li>
				578	<p>Example:</p>
				579
				580	<div class="source">
				581	<div class="source">
				582	<pre>use dataverse TinySocial;
				583
				584	let $s := "Hello ASTERIX!"
				585	let $l := string-to-codepoint($s)
				586	let $ss := codepoint-to-string($l)
				587	return {"codes": $l, "string": $ss}
				588	</pre></div></div></li>
				589	</ul>
				590
				591	<ul>
				592
				593	<li>
				594	<p>The expected result is:</p>
				595
				596	<div class="source">
				597	<div class="source">
				598	<pre>{ "codes": [ 72, 101, 108, 108, 111, 32, 65, 83, 84, 69, 82, 73, 88, 33 ], "string": "Hello ASTERIX!" }
				599	</pre></div></div></li>
				600	</ul></div>
				601	<div class="section">
				602	<h3><a name="contains"></a>contains</h3>
				603
				604	<ul>
				605
				606	<li>
				607	<p>Syntax:</p>
				608
				609	<div class="source">
				610	<div class="source">
				611	<pre>contains(string_expression, substring_to_contain)
				612	</pre></div></div></li>
				613
				614	<li>
				615	<p>Checks whether the string <tt>string_expression</tt> contains the string <tt>substring_to_contain</tt></p></li>
				616
				617	<li>Arguments:
				618
				619	<ul>
				620
				621	<li><tt>string_expression</tt> : A <tt>string</tt> that might contain the given substring.</li>
				622
				623	<li><tt>substring_to_contain</tt> : A target <tt>string</tt> that might be contained.</li>
				624	</ul></li>
				625
				626	<li>Return Value:
				627
				628	<ul>
				629
				630	<li>A <tt>boolean</tt> value, <tt>true</tt> if <tt>string_expression</tt> contains <tt>substring_to_contain</tt>, and <tt>false</tt> otherwise.</li>
				631	</ul></li>
				632
				633	<li>Note: An <a href="similarity.html#UsingIndexesToSupportSimilarityQueries">n-gram index</a> can be utilized for this function.</li>
				634
				635	<li>
				636	<p>Example:</p>
				637
				638	<div class="source">
				639	<div class="source">
				640	<pre>use dataverse TinySocial;
				641
				642	for $i in dataset('FacebookMessages')
				643	where contains($i.message, "phone")
				644	return {"mid": $i.message-id, "message": $i.message}
				645	</pre></div></div></li>
				646	</ul>
				647
				648	<ul>
				649
				650	<li>
				651	<p>The expected result is:</p>
				652
				653	<div class="source">
				654	<div class="source">
				655	<pre>{ "mid": 2, "message": " dislike iphone its touch-screen is horrible" }
				656	{ "mid": 13, "message": " dislike iphone the voice-command is bad:(" }
				657	{ "mid": 15, "message": " like iphone the voicemail-service is awesome" }
				658	</pre></div></div></li>
				659	</ul></div>
				660	<div class="section">
				661	<h3><a name="like"></a>like</h3>
				662
				663	<ul>
				664
				665	<li>
				666	<p>Syntax:</p>
				667
				668	<div class="source">
				669	<div class="source">
				670	<pre>like(string_expression, string_pattern)
				671	</pre></div></div></li>
				672
				673	<li>
				674	<p>Checks whether the string <tt>string_expression</tt> contains the string pattern <tt>string_pattern</tt>. Compared to the <tt>contains</tt> function, the <tt>like</tt> function also supports regular expressions.</p></li>
				675
				676	<li>Arguments:
				677
				678	<ul>
				679
				680	<li><tt>string_expression</tt> : A <tt>string</tt> that might contain the pattern or <tt>null</tt>.</li>
				681
				682	<li><tt>string_pattern</tt> : A pattern <tt>string</tt> that might be contained or <tt>null</tt>.</li>
				683	</ul></li>
				684
				685	<li>Return Value:
				686
				687	<ul>
				688
				689	<li>A <tt>boolean</tt> value, <tt>true</tt> if <tt>string_expression</tt> contains the pattern <tt>string_pattern</tt>, and <tt>false</tt> otherwise.</li>
				690	</ul></li>
				691
				692	<li>
				693	<p>Example:</p>
				694
				695	<div class="source">
				696	<div class="source">
				697	<pre>use dataverse TinySocial;
				698
				699	for $i in dataset('FacebookMessages')
				700	where like($i.message, "%at&t%")
				701	return $i.message
				702	</pre></div></div></li>
				703	</ul>
				704
				705	<ul>
				706
				707	<li>
				708	<p>The expected result is:</p>
				709
				710	<div class="source">
				711	<div class="source">
				712	<pre>" can't stand at&t the network is horrible:("
				713	" can't stand at&t its plan is terrible"
				714	" love at&t its 3G is good:)"
				715	</pre></div></div></li>
				716	</ul></div>
				717	<div class="section">
				718	<h3><a name="starts-with"></a>starts-with</h3>
				719
				720	<ul>
				721
				722	<li>
				723	<p>Syntax:</p>
				724
				725	<div class="source">
				726	<div class="source">
				727	<pre>starts-with(string_expression, substring_to_start_with)
				728	</pre></div></div></li>
				729
				730	<li>
				731	<p>Checks whether the string <tt>string_expression</tt> starts with the string <tt>substring_to_start_with</tt>.</p></li>
				732
				733	<li>Arguments:
				734
				735	<ul>
				736
				737	<li><tt>string_expression</tt> : A <tt>string</tt> that might start with the given string.</li>
				738
				739	<li><tt>substring_to_start_with</tt> : A <tt>string</tt> that might be contained as the starting substring.</li>
				740	</ul></li>
				741
				742	<li>Return Value:
				743
				744	<ul>
				745
				746	<li>A <tt>boolean</tt>, returns <tt>true</tt> if <tt>string_expression</tt> starts with the string <tt>substring_to_start_with</tt>, and <tt>false</tt> otherwise.</li>
				747	</ul></li>
				748
				749	<li>
				750	<p>Example:</p>
				751
				752	<div class="source">
				753	<div class="source">
				754	<pre>use dataverse TinySocial;
				755
				756	for $i in dataset('FacebookMessages')
				757	where starts-with($i.message, " like")
				758	return $i.message
				759	</pre></div></div></li>
				760	</ul>
				761
				762	<ul>
				763
				764	<li>
				765	<p>The expected result is:</p>
				766
				767	<div class="source">
				768	<div class="source">
				769	<pre>" like samsung the plan is amazing"
				770	" like t-mobile its platform is mind-blowing"
				771	" like verizon the 3G is awesome:)"
				772	" like iphone the voicemail-service is awesome"
				773	</pre></div></div></li>
				774	</ul></div>
				775	<div class="section">
				776	<h3><a name="ends-with"></a>ends-with</h3>
				777
				778	<ul>
				779
				780	<li>
				781	<p>Syntax:</p>
				782
				783	<div class="source">
				784	<div class="source">
				785	<pre>ends-with(string_expression, substring_to_end_with)
				786	</pre></div></div></li>
				787
				788	<li>
				789	<p>Checks whether the string <tt>string_expression</tt> ends with the string <tt>substring_to_end_with</tt>.</p></li>
				790
				791	<li>Arguments:
				792
				793	<ul>
				794
				795	<li><tt>string_expression</tt> : A <tt>string</tt> that might end with the given string.</li>
				796
				797	<li><tt>substring_to_end_with</tt> : A <tt>string</tt> that might be contained as the ending substring.</li>
				798	</ul></li>
				799
				800	<li>Return Value:
				801
				802	<ul>
				803
				804	<li>A <tt>boolean</tt>, returns <tt>true</tt> if <tt>string_expression</tt> ends with the string <tt>substring_to_end_with</tt>, and <tt>false</tt> otherwise.</li>
				805	</ul></li>
				806
				807	<li>
				808	<p>Example:</p>
				809
				810	<div class="source">
				811	<div class="source">
				812	<pre>use dataverse TinySocial;
				813
				814	for $i in dataset('FacebookMessages')
				815	where ends-with($i.message, ":)")
				816	return $i.message
				817	</pre></div></div></li>
				818	</ul>
				819
				820	<ul>
				821
				822	<li>
				823	<p>The expected result is:</p>
				824
				825	<div class="source">
				826	<div class="source">
				827	<pre>" love sprint its shortcut-menu is awesome:)"
				828	" like verizon the 3G is awesome:)"
				829	" love at&t its 3G is good:)"
				830	</pre></div></div></li>
				831	</ul></div>
				832	<div class="section">
				833	<h3><a name="string-concat"></a>string-concat</h3>
				834
				835	<ul>
				836
				837	<li>
				838	<p>Syntax:</p>
				839
				840	<div class="source">
				841	<div class="source">
				842	<pre>string-concat(list_expression)
				843	</pre></div></div></li>
				844
				845	<li>
				846	<p>Concatenates a list of strings <tt>list_expression</tt> into a single string.</p></li>
				847
				848	<li>Arguments:
				849
				850	<ul>
				851
				852	<li><tt>list_expression</tt> : An <tt>OrderedList</tt> or <tt>UnorderedList</tt> of <tt>string</tt>s (could be <tt>null</tt>) to be concatenated.</li>
				853	</ul></li>
				854
				855	<li>Return Value:
				856
				857	<ul>
				858
				859	<li>Returns the concatenated <tt>string</tt> value.</li>
				860	</ul></li>
				861
				862	<li>
				863	<p>Example:</p>
				864
				865	<div class="source">
				866	<div class="source">
				867	<pre>let $i := "ASTERIX"
				868	let $j := " "
				869	let $k := "ROCKS!"
				870	return string-concat([$i, $j, $k])
				871	</pre></div></div></li>
				872	</ul>
				873
				874	<ul>
				875
				876	<li>
				877	<p>The expected result is:</p>
				878
				879	<div class="source">
				880	<div class="source">
				881	<pre>"ASTERIX ROCKS!"
				882	</pre></div></div></li>
				883	</ul></div>
				884	<div class="section">
				885	<h3><a name="string-join"></a>string-join</h3>
				886
				887	<ul>
				888
				889	<li>
				890	<p>Syntax:</p>
				891
				892	<div class="source">
				893	<div class="source">
				894	<pre>string-join(list_expression, string_expression)
				895	</pre></div></div></li>
				896
				897	<li>
				898	<p>Joins a list of strings <tt>list_expression</tt> with the given separator <tt>string_expression</tt> into a single string.</p></li>
				899
				900	<li>Arguments:
				901
				902	<ul>
				903
				904	<li><tt>list_expression</tt> : An <tt>OrderedList</tt> or <tt>UnorderedList</tt> of strings (could be <tt>null</tt>) to be joined.</li>
				905
				906	<li><tt>string_expression</tt> : A <tt>string</tt> as the separator.</li>
				907	</ul></li>
				908
				909	<li>Return Value:
				910
				911	<ul>
				912
				913	<li>Returns the joined <tt>String</tt>.</li>
				914	</ul></li>
				915
				916	<li>
				917	<p>Example:</p>
				918
				919	<div class="source">
				920	<div class="source">
				921	<pre>use dataverse TinySocial;
				922
				923	let $i := ["ASTERIX", "ROCKS~"]
				924	return string-join($i, "!! ")
				925	</pre></div></div></li>
				926	</ul>
				927
				928	<ul>
				929
				930	<li>
				931	<p>The expected result is:</p>
				932
				933	<div class="source">
				934	<div class="source">
				935	<pre>"ASTERIX!! ROCKS~"
				936	</pre></div></div></li>
				937	</ul></div>
				938	<div class="section">
				939	<h3><a name="lowercase"></a>lowercase</h3>
				940
				941	<ul>
				942
				943	<li>
				944	<p>Syntax:</p>
				945
				946	<div class="source">
				947	<div class="source">
				948	<pre>lowercase(string_expression)
				949	</pre></div></div></li>
				950
				951	<li>
				952	<p>Converts a given string <tt>string_expression</tt> to its lowercase form.</p></li>
				953
				954	<li>Arguments:
				955
				956	<ul>
				957
				958	<li><tt>string_expression</tt> : A <tt>string</tt> to be converted.</li>
				959	</ul></li>
				960
				961	<li>Return Value:
				962
				963	<ul>
				964
				965	<li>Returns a <tt>string</tt> as the lowercase form of the given <tt>string_expression</tt>.</li>
				966	</ul></li>
				967
				968	<li>
				969	<p>Example:</p>
				970
				971	<div class="source">
				972	<div class="source">
				973	<pre>use dataverse TinySocial;
				974
				975	let $i := "ASTERIX"
				976	return lowercase($i)
				977	</pre></div></div></li>
				978	</ul>
				979
				980	<ul>
				981
				982	<li>
				983	<p>The expected result is:</p>
				984
				985	<div class="source">
				986	<div class="source">
				987	<pre>asterix
				988	</pre></div></div></li>
				989	</ul></div>
				990	<div class="section">
				991	<h3><a name="uppercase"></a>uppercase</h3>
				992
				993	<ul>
				994
				995	<li>Syntax:</li>
				996	</ul>
				997	<p>uppercase(string_expression)</p>
				998
				999	<ul>
				1000
				1001	<li>Converts a given string <tt>string_expression</tt> to its uppercase form.</li>
				1002
				1003	<li>Arguments:
				1004
				1005	<ul>
				1006
				1007	<li><tt>string_expression</tt> : A <tt>string</tt> to be converted.</li>
				1008	</ul></li>
				1009
				1010	<li>Return Value:
				1011
				1012	<ul>
				1013
				1014	<li>Returns a <tt>string</tt> as the uppercase form of the given <tt>string_expression</tt>.</li>
				1015	</ul></li>
				1016
				1017	<li>
				1018	<p>Example:</p>
				1019
				1020	<div class="source">
				1021	<div class="source">
				1022	<pre>use dataverse TinySocial;
				1023
				1024	let $i := "asterix"
				1025	return uppercase($i)
				1026	</pre></div></div></li>
				1027	</ul>
				1028
				1029	<ul>
				1030
				1031	<li>
				1032	<p>The expected result is:</p>
				1033
				1034	<div class="source">
				1035	<div class="source">
				1036	<pre>ASTERIX
				1037	</pre></div></div></li>
				1038	</ul></div>
				1039	<div class="section">
				1040	<h3><a name="uppercase"></a>uppercase</h3>
				1041
				1042	<ul>
				1043
				1044	<li>
				1045	<p>Syntax:</p>
				1046
				1047	<div class="source">
				1048	<div class="source">
				1049	<pre>uppercase(string_expression)
				1050	</pre></div></div></li>
				1051
				1052	<li>
				1053	<p>Converts a given string <tt>string_expression</tt> to its uppercase form.</p></li>
				1054
				1055	<li>Arguments:
				1056
				1057	<ul>
				1058
				1059	<li><tt>string_expression</tt> : A <tt>string</tt> to be converted.</li>
				1060	</ul></li>
				1061
				1062	<li>Return Value:
				1063
				1064	<ul>
				1065
				1066	<li>Returns a <tt>string</tt> as the uppercase form of the given <tt>string_expression</tt>.</li>
				1067	</ul></li>
				1068
				1069	<li>
				1070	<p>Example:</p>
				1071
				1072	<div class="source">
				1073	<div class="source">
				1074	<pre>use dataverse TinySocial;
				1075
				1076	let $i := "asterix"
				1077	return uppercase($i)
				1078	</pre></div></div></li>
				1079	</ul>
				1080
				1081	<ul>
				1082
				1083	<li>
				1084	<p>The expected result is:</p>
				1085
				1086	<div class="source">
				1087	<div class="source">
				1088	<pre>ASTERIX
				1089	</pre></div></div></li>
				1090	</ul></div>
				1091	<div class="section">
				1092	<h3><a name="matches"></a>matches</h3>
				1093
				1094	<ul>
				1095
				1096	<li>
				1097	<p>Syntax:</p>
				1098
				1099	<div class="source">
				1100	<div class="source">
				1101	<pre>matches(string_expression, string_pattern)
				1102	</pre></div></div></li>
				1103
				1104	<li>
				1105	<p>Checks whether the strings <tt>string_expression</tt> matches the given pattern <tt>string_pattern</tt> (A Java regular expression pattern).</p></li>
				1106
				1107	<li>Arguments:
				1108
				1109	<ul>
				1110
				1111	<li><tt>string_expression</tt> : A <tt>string</tt> that might contain the pattern.</li>
				1112
				1113	<li><tt>string_pattern</tt> : A pattern <tt>string</tt> to be matched.</li>
				1114	</ul></li>
				1115
				1116	<li>Return Value:
				1117
				1118	<ul>
				1119
				1120	<li>A <tt>boolean</tt>, returns <tt>true</tt> if <tt>string_expression</tt> matches the pattern <tt>string_pattern</tt>, and <tt>false</tt> otherwise.</li>
				1121	</ul></li>
				1122
				1123	<li>
				1124	<p>Example:</p>
				1125
				1126	<div class="source">
				1127	<div class="source">
				1128	<pre>use dataverse TinySocial;
				1129
				1130	for $i in dataset('FacebookMessages')
				1131	where matches($i.message, "dislike iphone")
				1132	return $i.message
				1133	</pre></div></div></li>
				1134	</ul>
				1135
				1136	<ul>
				1137
				1138	<li>
				1139	<p>The expected result is:</p>
				1140
				1141	<div class="source">
				1142	<div class="source">
				1143	<pre>" dislike iphone its touch-screen is horrible"
				1144	" dislike iphone the voice-command is bad:("
				1145	</pre></div></div></li>
				1146	</ul></div>
				1147	<div class="section">
				1148	<h3><a name="replace"></a>replace</h3>
				1149
				1150	<ul>
				1151
				1152	<li>
				1153	<p>Syntax:</p>
				1154
				1155	<div class="source">
				1156	<div class="source">
				1157	<pre>replace(string_expression, string_pattern, string_replacement[, string_flags])
				1158	</pre></div></div></li>
				1159
				1160	<li>
				1161	<p>Checks whether the string <tt>string_expression</tt> matches the given pattern <tt>string_pattern</tt>, and replace the matched pattern <tt>string_pattern</tt> with the new pattern <tt>string_replacement</tt>.</p></li>
				1162
				1163	<li>Arguments:
				1164
				1165	<ul>
				1166
				1167	<li><tt>string_expression</tt> : A <tt>string</tt> that might contain the pattern.</li>
				1168
				1169	<li><tt>string_pattern</tt> : A pattern <tt>string</tt> to be matched.</li>
				1170
				1171	<li><tt>string_replacement</tt> : A pattern <tt>string</tt> to be used as the replacement.</li>
				1172
				1173	<li><tt>string_flag</tt> : (Optional) A <tt>string</tt> with flags to be used during replace.</li>
				1174
				1175	<li>The following modes are enabled with these flags: dotall (s), multiline (m), case-insenitive (i), and comments and whitespace (x).</li>
				1176	</ul></li>
				1177
				1178	<li>Return Value:
				1179
				1180	<ul>
				1181
				1182	<li>Returns a <tt>string</tt> that is obtained after the replacements.</li>
				1183	</ul></li>
				1184
				1185	<li>
				1186	<p>Example:</p>
				1187
				1188	<div class="source">
				1189	<div class="source">
				1190	<pre>use dataverse TinySocial;
				1191
				1192	for $i in dataset('FacebookMessages')
				1193	where matches($i.message, " like iphone")
				1194	return replace($i.message, " like iphone", "like android")
				1195	</pre></div></div></li>
				1196	</ul>
				1197
				1198	<ul>
				1199
				1200	<li>
				1201	<p>The expected result is:</p>
				1202
				1203	<div class="source">
				1204	<div class="source">
				1205	<pre>"like android the voicemail-service is awesome"
				1206	</pre></div></div></li>
				1207	</ul></div>
				1208	<div class="section">
				1209	<h3><a name="string-length"></a>string-length</h3>
				1210
				1211	<ul>
				1212
				1213	<li>
				1214	<p>Syntax:</p>
				1215
				1216	<div class="source">
				1217	<div class="source">
				1218	<pre>string-length(string_expression)
				1219	</pre></div></div></li>
				1220
				1221	<li>
				1222	<p>Returns the length of the string <tt>string_expression</tt>.</p></li>
				1223
				1224	<li>Arguments:
				1225
				1226	<ul>
				1227
				1228	<li><tt>string_expression</tt> : A <tt>string</tt> or <tt>null</tt> that represents the string to be checked.</li>
				1229	</ul></li>
				1230
				1231	<li>Return Value:
				1232
				1233	<ul>
				1234
				1235	<li>An <tt>int64</tt> that represents the length of <tt>string_expression</tt>.</li>
				1236	</ul></li>
				1237
				1238	<li>
				1239	<p>Example:</p>
				1240
				1241	<div class="source">
				1242	<div class="source">
				1243	<pre>use dataverse TinySocial;
				1244
				1245	for $i in dataset('FacebookMessages')
				1246	return {"mid": $i.message-id, "message-len": string-length($i.message)}
				1247	</pre></div></div></li>
				1248	</ul>
				1249
				1250	<ul>
				1251
				1252	<li>
				1253	<p>The expected result is:</p>
				1254
				1255	<div class="source">
				1256	<div class="source">
				1257	<pre>{ "mid": 1, "message-len": 43 }
				1258	{ "mid": 2, "message-len": 44 }
				1259	{ "mid": 3, "message-len": 33 }
				1260	{ "mid": 4, "message-len": 43 }
				1261	{ "mid": 5, "message-len": 46 }
				1262	{ "mid": 6, "message-len": 43 }
				1263	{ "mid": 7, "message-len": 37 }
				1264	{ "mid": 8, "message-len": 33 }
				1265	{ "mid": 9, "message-len": 34 }
				1266	{ "mid": 10, "message-len": 50 }
				1267	{ "mid": 11, "message-len": 38 }
				1268	{ "mid": 12, "message-len": 52 }
				1269	{ "mid": 13, "message-len": 42 }
				1270	{ "mid": 14, "message-len": 27 }
				1271	{ "mid": 15, "message-len": 45 }
				1272	</pre></div></div></li>
				1273	</ul></div>
				1274	<div class="section">
				1275	<h3><a name="substring"></a>substring</h3>
				1276
				1277	<ul>
				1278
				1279	<li>
				1280	<p>Syntax:</p>
				1281
				1282	<div class="source">
				1283	<div class="source">
				1284	<pre>substring(string_expression, offset[, length])
				1285	</pre></div></div></li>
				1286
				1287	<li>
				1288	<p>Returns the substring from the given string <tt>string_expression</tt> based on the given start offset <tt>offset</tt> with the optional <tt>length</tt>.</p></li>
				1289
				1290	<li>Arguments:
				1291
				1292	<ul>
				1293
				1294	<li><tt>string_expression</tt> : A <tt>string</tt> to be extracted.</li>
				1295
				1296	<li><tt>offset</tt> : An <tt>int64</tt> as the starting offset of the substring in <tt>string_expression</tt>.</li>
				1297
				1298	<li><tt>length</tt> : (Optional) An <tt>int64</tt> as the length of the substring.</li>
				1299	</ul></li>
				1300
				1301	<li>Return Value:
				1302
				1303	<ul>
				1304
				1305	<li>A <tt>string</tt> that represents the substring.</li>
				1306	</ul></li>
				1307
				1308	<li>
				1309	<p>Example:</p>
				1310
				1311	<div class="source">
				1312	<div class="source">
				1313	<pre>use dataverse TinySocial;
				1314
				1315	for $i in dataset('FacebookMessages')
				1316	where string-length($i.message) > 50
				1317	return substring($i.message, 50)
				1318	</pre></div></div></li>
				1319	</ul>
				1320
				1321	<ul>
				1322
				1323	<li>
				1324	<p>The expected result is:</p>
				1325
				1326	<div class="source">
				1327	<div class="source">
				1328	<pre>"G:("
				1329	</pre></div></div></li>
				1330	</ul></div>
				1331	<div class="section">
				1332	<h3><a name="substring-before"></a>substring-before</h3>
				1333
				1334	<ul>
				1335
				1336	<li>
				1337	<p>Syntax:</p>
				1338
				1339	<div class="source">
				1340	<div class="source">
				1341	<pre>substring-before(string_expression, string_pattern)
				1342	</pre></div></div></li>
				1343
				1344	<li>
				1345	<p>Returns the substring from the given string <tt>string_expression</tt> before the given pattern <tt>string_pattern</tt>.</p></li>
				1346
				1347	<li>Arguments:
				1348
				1349	<ul>
				1350
				1351	<li><tt>string_expression</tt> : A <tt>string</tt> to be extracted.</li>
				1352
				1353	<li><tt>string_pattern</tt> : A <tt>string</tt> pattern to be searched.</li>
				1354	</ul></li>
				1355
				1356	<li>Return Value:
				1357
				1358	<ul>
				1359
				1360	<li>A <tt>string</tt> that represents the substring.</li>
				1361	</ul></li>
				1362
				1363	<li>
				1364	<p>Example:</p>
				1365
				1366	<div class="source">
				1367	<div class="source">
				1368	<pre>use dataverse TinySocial;
				1369
				1370	for $i in dataset('FacebookMessages')
				1371	where contains($i.message, "iphone")
				1372	return substring-before($i.message, "iphone")
				1373	</pre></div></div></li>
				1374	</ul>
				1375
				1376	<ul>
				1377
				1378	<li>
				1379	<p>The expected result is:</p>
				1380
				1381	<div class="source">
				1382	<div class="source">
				1383	<pre>" dislike "
				1384	" dislike "
				1385	" like "
				1386	</pre></div></div></li>
				1387	</ul></div>
				1388	<div class="section">
				1389	<h3><a name="substring-after"></a>substring-after</h3>
				1390
				1391	<ul>
				1392
				1393	<li>
				1394	<p>Syntax:</p>
				1395
				1396	<div class="source">
				1397	<div class="source">
				1398	<pre>substring-after(string_expression, string_pattern)
				1399	</pre></div></div></li>
				1400
				1401	<li>
				1402	<p>Returns the substring from the given string <tt>string_expression</tt> after the given pattern <tt>string_pattern</tt>.</p></li>
				1403
				1404	<li>Arguments:
				1405
				1406	<ul>
				1407
				1408	<li><tt>string_expression</tt> : A <tt>string</tt> to be extracted.</li>
				1409
				1410	<li><tt>string_pattern</tt> : A <tt>string</tt> pattern to be searched.</li>
				1411	</ul></li>
				1412
				1413	<li>Return Value:
				1414
				1415	<ul>
				1416
				1417	<li>A <tt>string</tt> that represents the substring.</li>
				1418	</ul></li>
				1419
				1420	<li>
				1421	<p>Example:</p>
				1422
				1423	<div class="source">
				1424	<div class="source">
				1425	<pre>use dataverse TinySocial;
				1426
				1427	for $i in dataset('FacebookMessages')
				1428	where contains($i.message, "iphone")
				1429	return substring-after($i.message, "iphone")
				1430	</pre></div></div></li>
				1431	</ul>
				1432
				1433	<ul>
				1434
				1435	<li>
				1436	<p>The expected result is:</p>
				1437
				1438	<div class="source">
				1439	<div class="source">
				1440	<pre>" its touch-screen is horrible"
				1441	" the voice-command is bad:("
				1442	" the voicemail-service is awesome"
				1443	</pre></div></div></li>
				1444	</ul></div></div>
				1445	<div class="section">
				1446	<h2><a name="Aggregate_Functions_Back_to_TOC"></a><a name="AggregateFunctions" id="AggregateFunctions">Aggregate Functions</a> <font size="4"><a href="#toc">[Back to TOC]</a></font></h2>
				1447	<div class="section">
				1448	<h3><a name="count"></a>count</h3>
				1449
				1450	<ul>
				1451
				1452	<li>
				1453	<p>Syntax:</p>
				1454
				1455	<div class="source">
				1456	<div class="source">
				1457	<pre>count(list)
				1458	</pre></div></div></li>
				1459
				1460	<li>
				1461	<p>Gets the number of items in the given list.</p></li>
				1462
				1463	<li>Arguments:
				1464
				1465	<ul>
				1466
				1467	<li><tt>list</tt>: An <tt>orderedList</tt> or <tt>unorderedList</tt> containing the items to be counted, or a <tt>null</tt> value.</li>
				1468	</ul></li>
				1469
				1470	<li>Return Value:
				1471
				1472	<ul>
				1473
				1474	<li>An <tt>int64</tt> value representing the number of items in the given list. <tt>0i64</tt> is returned if the input is <tt>null</tt>.</li>
				1475	</ul></li>
				1476
				1477	<li>
				1478	<p>Example:</p>
				1479
				1480	<div class="source">
				1481	<div class="source">
				1482	<pre>use dataverse TinySocial;
				1483
				1484	let $l1 := ['hello', 'world', 1, 2, 3]
				1485	let $l2 := for $i in dataset TwitterUsers return $i
				1486	return {"count1": count($l1), "count2": count($l2)}
				1487	</pre></div></div></li>
				1488
				1489	<li>
				1490	<p>The expected result is:</p>
				1491
				1492	<div class="source">
				1493	<div class="source">
				1494	<pre>{ "count1": 5i64, "count2": 4i64 }
				1495	</pre></div></div></li>
				1496	</ul></div>
				1497	<div class="section">
				1498	<h3><a name="avg"></a>avg</h3>
				1499
				1500	<ul>
				1501
				1502	<li>
				1503	<p>Syntax:</p>
				1504
				1505	<div class="source">
				1506	<div class="source">
				1507	<pre>avg(num_list)
				1508	</pre></div></div></li>
				1509
				1510	<li>
				1511	<p>Gets the average value of the items in the given list.</p></li>
				1512
				1513	<li>Arguments:
				1514
				1515	<ul>
				1516
				1517	<li><tt>num_list</tt>: An <tt>orderedList</tt> or <tt>unorderedList</tt> containing numeric or null values, or a <tt>null</tt> value.</li>
				1518	</ul></li>
				1519
				1520	<li>Return Value:
				1521
				1522	<ul>
				1523
				1524	<li>An <tt>double</tt> value representing the average of the numbers in the given list. <tt>null</tt> is returned if the input is <tt>null</tt>, or the input list contains <tt>null</tt>. Non-numeric types in the input list will cause an error.</li>
				1525	</ul></li>
				1526
				1527	<li>
				1528	<p>Example:</p>
				1529
				1530	<div class="source">
				1531	<div class="source">
				1532	<pre>use dataverse TinySocial;
				1533
				1534	let $l := for $i in dataset TwitterUsers return $i.friends_count
				1535	return {"avg_friend_count": avg($l)}
				1536	</pre></div></div></li>
				1537
				1538	<li>
				1539	<p>The expected result is:</p>
				1540
				1541	<div class="source">
				1542	<div class="source">
				1543	<pre>{ "avg_friend_count": 191.5d }
				1544	</pre></div></div></li>
				1545	</ul></div>
				1546	<div class="section">
				1547	<h3><a name="sum"></a>sum</h3>
				1548
				1549	<ul>
				1550
				1551	<li>
				1552	<p>Syntax:</p>
				1553
				1554	<div class="source">
				1555	<div class="source">
				1556	<pre>sum(num_list)
				1557	</pre></div></div></li>
				1558
				1559	<li>
				1560	<p>Gets the sum of the items in the given list.</p></li>
				1561
				1562	<li>Arguments:
				1563
				1564	<ul>
				1565
				1566	<li><tt>num_list</tt>: An <tt>orderedList</tt> or <tt>unorderedList</tt> containing numeric or null values, or a <tt>null</tt> value.</li>
				1567	</ul></li>
				1568
				1569	<li>Return Value:
				1570
				1571	<ul>
				1572
				1573	<li>The sum of the numbers in the given list. The returning type is decided by the item type with the highest order in the numeric type promotion order (<tt>int8</tt>-> <tt>int16</tt>-><tt>int32</tt>-><tt>int64</tt>-><tt>float</tt>-><tt>double</tt>) among items. <tt>null</tt> is returned if the input is <tt>null</tt>, or the input list contains <tt>null</tt>. Non-numeric types in the input list will cause an error.</li>
				1574	</ul></li>
				1575
				1576	<li>
				1577	<p>Example:</p>
				1578
				1579	<div class="source">
				1580	<div class="source">
				1581	<pre>use dataverse TinySocial;
				1582
				1583	let $l := for $i in dataset TwitterUsers return $i.friends_count
				1584	return {"sum_friend_count": sum($l)}
				1585	</pre></div></div></li>
				1586
				1587	<li>
				1588	<p>The expected result is:</p>
				1589
				1590	<div class="source">
				1591	<div class="source">
				1592	<pre>{ "sum_friend_count": 766 }
				1593	</pre></div></div></li>
				1594	</ul></div>
				1595	<div class="section">
				1596	<h3><a name="minmax"></a>min/max</h3>
				1597
				1598	<ul>
				1599
				1600	<li>
				1601	<p>Syntax:</p>
				1602
				1603	<div class="source">
				1604	<div class="source">
				1605	<pre>min(num_list), max(num_list)
				1606	</pre></div></div></li>
				1607
				1608	<li>
				1609	<p>Gets the min/max value of numeric items in the given list.</p></li>
				1610
				1611	<li>Arguments:
				1612
				1613	<ul>
				1614
				1615	<li><tt>num_list</tt>: An <tt>orderedList</tt> or <tt>unorderedList</tt> containing the items to be compared, or a <tt>null</tt> value.</li>
				1616	</ul></li>
				1617
				1618	<li>Return Value:
				1619
				1620	<ul>
				1621
				1622	<li>The min/max value of the given list. The returning type is decided by the item type with the highest order in the numeric type promotion order (<tt>int8</tt>-> <tt>int16</tt>-><tt>int32</tt>-><tt>int64</tt>-><tt>float</tt>-><tt>double</tt>) among items. <tt>null</tt> is returned if the input is <tt>null</tt>, or the input list contains <tt>null</tt>. Non-numeric types in the input list will cause an error.</li>
				1623	</ul></li>
				1624
				1625	<li>
				1626	<p>Example:</p>
				1627
				1628	<div class="source">
				1629	<div class="source">
				1630	<pre>use dataverse TinySocial;
				1631
				1632	let $l := for $i in dataset TwitterUsers return $i. friends_count
				1633	return {"min_friend_count": min($l), "max_friend_count": max($l)}
				1634	</pre></div></div></li>
				1635
				1636	<li>
				1637	<p>The expected result is:</p>
				1638
				1639	<div class="source">
				1640	<div class="source">
				1641	<pre>{ "min_friend_count": 18, "max_friend_count": 445 }
				1642	</pre></div></div></li>
				1643	</ul></div>
				1644	<div class="section">
				1645	<h3><a name="sql-count"></a>sql-count</h3>
				1646
				1647	<ul>
				1648
				1649	<li>
				1650	<p>Syntax:</p>
				1651
				1652	<div class="source">
				1653	<div class="source">
				1654	<pre>sql-count(list)
				1655	</pre></div></div></li>
				1656
				1657	<li>
				1658	<p>Gets the number of non-null items in the given list.</p></li>
				1659
				1660	<li>Arguments:
				1661
				1662	<ul>
				1663
				1664	<li><tt>list</tt>: An <tt>orderedList</tt> or <tt>unorderedList</tt> containing the items to be counted, or a <tt>null</tt> value.</li>
				1665	</ul></li>
				1666
				1667	<li>Return Value:
				1668
				1669	<ul>
				1670
				1671	<li>An <tt>int64</tt> value representing the number of non-null items in the given list. The value <tt>0i64</tt> is returned if the input is <tt>null</tt>.</li>
				1672	</ul></li>
				1673
				1674	<li>
				1675	<p>Example:</p></li>
				1676	</ul>
				1677
				1678	<div class="source">
				1679	<div class="source">
				1680	<pre> let $l1 := ['hello', 'world', 1, 2, 3, null]
				1681	return {"count": sql-count($l1)}
				1682	</pre></div></div>
				1683
				1684	<ul>
				1685
				1686	<li>
				1687	<p>The expected result is:</p>
				1688
				1689	<div class="source">
				1690	<div class="source">
				1691	<pre>{ "count": 5i64 }
				1692	</pre></div></div></li>
				1693	</ul></div>
				1694	<div class="section">
				1695	<h3><a name="sql-avg"></a>sql-avg</h3>
				1696
				1697	<ul>
				1698
				1699	<li>
				1700	<p>Syntax:</p>
				1701
				1702	<div class="source">
				1703	<div class="source">
				1704	<pre>sql-avg(num_list)
				1705	</pre></div></div></li>
				1706
				1707	<li>
				1708	<p>Gets the average value of the non-null items in the given list.</p></li>
				1709
				1710	<li>Arguments:
				1711
				1712	<ul>
				1713
				1714	<li><tt>num_list</tt>: An <tt>orderedList</tt> or <tt>unorderedList</tt> containing numeric or null values, or a <tt>null</tt> value.</li>
				1715	</ul></li>
				1716
				1717	<li>Return Value:
				1718
				1719	<ul>
				1720
				1721	<li>A <tt>double</tt> value representing the average of the non-null numbers in the given list. The <tt>null</tt> value is returned if the input is <tt>null</tt>. Non-numeric types in the input list will cause an error.</li>
				1722	</ul></li>
				1723
				1724	<li>
				1725	<p>Example:</p>
				1726
				1727	<div class="source">
				1728	<div class="source">
				1729	<pre>let $l := [1.2, 2.3, 3.4, 0, null]
				1730	return {"avg": sql-avg($l)}
				1731	</pre></div></div></li>
				1732
				1733	<li>
				1734	<p>The expected result is:</p>
				1735
				1736	<div class="source">
				1737	<div class="source">
				1738	<pre>{ "avg": 1.725d }
				1739	</pre></div></div></li>
				1740	</ul></div>
				1741	<div class="section">
				1742	<h3><a name="sql-sum"></a>sql-sum</h3>
				1743
				1744	<ul>
				1745
				1746	<li>
				1747	<p>Syntax:</p>
				1748
				1749	<div class="source">
				1750	<div class="source">
				1751	<pre>sql-sum(num_list)
				1752	</pre></div></div></li>
				1753
				1754	<li>
				1755	<p>Gets the sum of the non-null items in the given list.</p></li>
				1756
				1757	<li>Arguments:
				1758
				1759	<ul>
				1760
				1761	<li><tt>num_list</tt>: An <tt>orderedList</tt> or <tt>unorderedList</tt> containing numeric or null values, or a <tt>null</tt> value.</li>
				1762	</ul></li>
				1763
				1764	<li>Return Value:
				1765
				1766	<ul>
				1767
				1768	<li>The sum of the non-null numbers in the given list. The returning type is decided by the item type with the highest order in the numeric type promotion order (<tt>int8</tt>-> <tt>int16</tt>-><tt>int32</tt>-><tt>int64</tt>-><tt>float</tt>-><tt>double</tt>) among items. The value <tt>null</tt> is returned if the input is <tt>null</tt>. Non-numeric types in the input list will cause an error.</li>
				1769	</ul></li>
				1770
				1771	<li>
				1772	<p>Example:</p>
				1773
				1774	<div class="source">
				1775	<div class="source">
				1776	<pre>let $l := [1.2, 2.3, 3.4, 0, null]
				1777	return {"sum": sql-sum($l)}
				1778	</pre></div></div></li>
				1779
				1780	<li>
				1781	<p>The expected result is:</p>
				1782
				1783	<div class="source">
				1784	<div class="source">
				1785	<pre>{ "sum": 6.9d }
				1786	</pre></div></div></li>
				1787	</ul></div>
				1788	<div class="section">
				1789	<h3><a name="sql-minmax"></a>sql-min/max</h3>
				1790
				1791	<ul>
				1792
				1793	<li>
				1794	<p>Syntax:</p>
				1795
				1796	<div class="source">
				1797	<div class="source">
				1798	<pre>sql-min(num_list), sql-max(num_list)
				1799	</pre></div></div></li>
				1800
				1801	<li>
				1802	<p>Gets the min/max value of the non-null numeric items in the given list.</p></li>
				1803
				1804	<li>Arguments:
				1805
				1806	<ul>
				1807
				1808	<li><tt>num_list</tt>: An <tt>orderedList</tt> or <tt>unorderedList</tt> containing the items to be compared, or a <tt>null</tt> value.</li>
				1809	</ul></li>
				1810
				1811	<li>Return Value:
				1812
				1813	<ul>
				1814
				1815	<li>The min/max value of the given list. The returning type is decided by the item type with the highest order in the numeric type promotion order (<tt>int8</tt>-> <tt>int16</tt>-><tt>int32</tt>-><tt>int64</tt>-><tt>float</tt>-><tt>double</tt>) among items. The value <tt>null</tt> is returned if the input is <tt>null</tt>. Non-numeric types in the input list will cause an error.</li>
				1816	</ul></li>
				1817
				1818	<li>
				1819	<p>Example:</p>
				1820
				1821	<div class="source">
				1822	<div class="source">
				1823	<pre>let $l := [1.2, 2.3, 3.4, 0, null]
				1824	return {"min": sql-min($l), "max": sql-max($l)}
				1825	</pre></div></div></li>
				1826
				1827	<li>
				1828	<p>The expected result is:</p>
				1829
				1830	<div class="source">
				1831	<div class="source">
				1832	<pre>{ "min": 0.0d, "max": 3.4d }
				1833	</pre></div></div></li>
				1834	</ul></div></div>
				1835	<div class="section">
				1836	<h2><a name="Spatial_Functions_Back_to_TOC"></a><a name="SpatialFunctions" id="SpatialFunctions">Spatial Functions</a> <font size="4"><a href="#toc">[Back to TOC]</a></font></h2>
				1837	<div class="section">
				1838	<h3><a name="create-point"></a>create-point</h3>
				1839
				1840	<ul>
				1841
				1842	<li>
				1843	<p>Syntax:</p>
				1844
				1845	<div class="source">
				1846	<div class="source">
				1847	<pre>create-point(x, y)
				1848	</pre></div></div></li>
				1849
				1850	<li>
				1851	<p>Creates the primitive type <tt>point</tt> using an <tt>x</tt> and <tt>y</tt> value.</p></li>
				1852
				1853	<li>Arguments:</li>
				1854
				1855	<li><tt>x</tt> : A <tt>double</tt> that represents the x-coordinate.</li>
				1856
				1857	<li><tt>y</tt> : A <tt>double</tt> that represents the y-coordinate.</li>
				1858
				1859	<li>Return Value:</li>
				1860
				1861	<li>A <tt>point</tt> representing the ordered pair (<tt>x</tt>, <tt>y</tt>).</li>
				1862
				1863	<li>
				1864	<p>Example:</p>
				1865
				1866	<div class="source">
				1867	<div class="source">
				1868	<pre>use dataverse TinySocial;
				1869
				1870	let $c := create-point(30.0,70.0)
				1871	return {"point": $c}
				1872	</pre></div></div></li>
				1873	</ul>
				1874
				1875	<ul>
				1876
				1877	<li>
				1878	<p>The expected result is:</p>
				1879
				1880	<div class="source">
				1881	<div class="source">
				1882	<pre>{ "point": point("30.0,70.0") }
				1883	</pre></div></div></li>
				1884	</ul></div>
				1885	<div class="section">
				1886	<h3><a name="create-line"></a>create-line</h3>
				1887
				1888	<ul>
				1889
				1890	<li>
				1891	<p>Syntax:</p>
				1892
				1893	<div class="source">
				1894	<div class="source">
				1895	<pre>create-line(point_expression1, point_expression2)
				1896	</pre></div></div></li>
				1897
				1898	<li>
				1899	<p>Creates the primitive type <tt>line</tt> using <tt>point_expression1</tt> and <tt>point_expression2</tt>.</p></li>
				1900
				1901	<li>Arguments:
				1902
				1903	<ul>
				1904
				1905	<li><tt>point_expression1</tt> : A <tt>point</tt> that represents the start point of the line.</li>
				1906
				1907	<li><tt>point_expression2</tt> : A <tt>point</tt> that represents the end point of the line.</li>
				1908	</ul></li>
				1909
				1910	<li>Return Value:
				1911
				1912	<ul>
				1913
				1914	<li>A spatial <tt>line</tt> created using the points provided in <tt>point_expression1</tt> and <tt>point_expression2</tt>.</li>
				1915	</ul></li>
				1916
				1917	<li>
				1918	<p>Example:</p>
				1919
				1920	<div class="source">
				1921	<div class="source">
				1922	<pre>use dataverse TinySocial;
				1923
				1924	let $c := create-line(create-point(30.0,70.0), create-point(50.0,90.0))
				1925	return {"line": $c}
				1926	</pre></div></div></li>
				1927	</ul>
				1928
				1929	<ul>
				1930
				1931	<li>
				1932	<p>The expected result is:</p>
				1933
				1934	<div class="source">
				1935	<div class="source">
				1936	<pre>{ "line": line("30.0,70.0 50.0,90.0") }
				1937	</pre></div></div></li>
				1938	</ul></div>
				1939	<div class="section">
				1940	<h3><a name="create-rectangle"></a>create-rectangle</h3>
				1941
				1942	<ul>
				1943
				1944	<li>
				1945	<p>Syntax:</p>
				1946
				1947	<div class="source">
				1948	<div class="source">
				1949	<pre>create-rectangle(point_expression1, point_expression2)
				1950	</pre></div></div></li>
				1951
				1952	<li>
				1953	<p>Creates the primitive type <tt>rectangle</tt> using <tt>point_expression1</tt> and <tt>point_expression2</tt>.</p></li>
				1954
				1955	<li>Arguments:
				1956
				1957	<ul>
				1958
				1959	<li><tt>point_expression1</tt> : A <tt>point</tt> that represents the lower-left point of the rectangle.</li>
				1960
				1961	<li><tt>point_expression2</tt> : A <tt>point</tt> that represents the upper-right point of the rectangle.</li>
				1962	</ul></li>
				1963
				1964	<li>Return Value:
				1965
				1966	<ul>
				1967
				1968	<li>A spatial <tt>rectangle</tt> created using the points provided in <tt>point_expression1</tt> and <tt>point_expression2</tt>.</li>
				1969	</ul></li>
				1970
				1971	<li>
				1972	<p>Example:</p>
				1973
				1974	<div class="source">
				1975	<div class="source">
				1976	<pre>use dataverse TinySocial;
				1977
				1978	let $c := create-rectangle(create-point(30.0,70.0), create-point(50.0,90.0))
				1979	return {"rectangle": $c}
				1980	</pre></div></div></li>
				1981	</ul>
				1982
				1983	<ul>
				1984
				1985	<li>
				1986	<p>The expected result is:</p>
				1987
				1988	<div class="source">
				1989	<div class="source">
				1990	<pre>{ "rectangle": rectangle("30.0,70.0 50.0,90.0") }
				1991	</pre></div></div></li>
				1992	</ul></div>
				1993	<div class="section">
				1994	<h3><a name="create-circle"></a>create-circle</h3>
				1995
				1996	<ul>
				1997
				1998	<li>
				1999	<p>Syntax:</p>
				2000
				2001	<div class="source">
				2002	<div class="source">
				2003	<pre>create-circle(point_expression, radius)
				2004	</pre></div></div></li>
				2005
				2006	<li>
				2007	<p>Creates the primitive type <tt>circle</tt> using <tt>point_expression</tt> and <tt>radius</tt>.</p></li>
				2008
				2009	<li>Arguments:
				2010
				2011	<ul>
				2012
				2013	<li><tt>point_expression</tt> : A <tt>point</tt> that represents the center of the circle.</li>
				2014
				2015	<li><tt>radius</tt> : A <tt>double</tt> that represents the radius of the circle.</li>
				2016	</ul></li>
				2017
				2018	<li>Return Value:
				2019
				2020	<ul>
				2021
				2022	<li>A spatial <tt>circle</tt> created using the center point and the radius provided in <tt>point_expression</tt> and <tt>radius</tt>.</li>
				2023	</ul></li>
				2024
				2025	<li>
				2026	<p>Example:</p>
				2027
				2028	<div class="source">
				2029	<div class="source">
				2030	<pre>use dataverse TinySocial;
				2031
				2032	let $c := create-circle(create-point(30.0,70.0), 5.0)
				2033	return {"circle": $c}
				2034	</pre></div></div></li>
				2035	</ul>
				2036
				2037	<ul>
				2038
				2039	<li>
				2040	<p>The expected result is:</p>
				2041
				2042	<div class="source">
				2043	<div class="source">
				2044	<pre>{ "circle": circle("30.0,70.0 5.0") }
				2045	</pre></div></div></li>
				2046	</ul></div>
				2047	<div class="section">
				2048	<h3><a name="create-polygon"></a>create-polygon</h3>
				2049
				2050	<ul>
				2051
				2052	<li>
				2053	<p>Syntax:</p>
				2054
				2055	<div class="source">
				2056	<div class="source">
				2057	<pre>create-polygon(list_expression)
				2058	</pre></div></div></li>
				2059
				2060	<li>
				2061	<p>Creates the primitive type <tt>polygon</tt> using the double values provided in the argument <tt>list_expression</tt>. Each two consecutive double values represent a point starting from the first double value in the list. Note that at least six double values should be specified, meaning a total of three points.</p></li>
				2062
				2063	<li>Arguments:</li>
				2064
				2065	<li><tt>list_expression</tt> : An OrderedList of doubles representing the points of the polygon.</li>
				2066
				2067	<li>Return Value:</li>
				2068
				2069	<li>A <tt>polygon</tt>, represents a spatial simple polygon created using the points provided in <tt>list_expression</tt>.</li>
				2070
				2071	<li>
				2072	<p>Example:</p>
				2073
				2074	<div class="source">
				2075	<div class="source">
				2076	<pre>use dataverse TinySocial;
				2077
				2078	let $c := create-polygon([1.0,1.0,2.0,2.0,3.0,3.0,4.0,4.0])
				2079	return {"polygon": $c}
				2080	</pre></div></div></li>
				2081	</ul>
				2082
				2083	<ul>
				2084
				2085	<li>
				2086	<p>The expected result is:</p>
				2087
				2088	<div class="source">
				2089	<div class="source">
				2090	<pre>{ "polygon": polygon("1.0,1.0 2.0,2.0 3.0,3.0 4.0,4.0") }
				2091	</pre></div></div></li>
				2092	</ul></div>
				2093	<div class="section">
				2094	<h3><a name="get-xget-y"></a>get-x/get-y</h3>
				2095
				2096	<ul>
				2097
				2098	<li>
				2099	<p>Syntax:</p>
				2100
				2101	<div class="source">
				2102	<div class="source">
				2103	<pre>get-x(point_expression) or get-y(point_expression)
				2104	</pre></div></div></li>
				2105
				2106	<li>
				2107	<p>Returns the x or y coordinates of a point <tt>point_expression</tt>.</p></li>
				2108
				2109	<li>Arguments:
				2110
				2111	<ul>
				2112
				2113	<li><tt>point_expression</tt> : A <tt>point</tt>.</li>
				2114	</ul></li>
				2115
				2116	<li>Return Value:
				2117
				2118	<ul>
				2119
				2120	<li>A <tt>double</tt> representing the x or y coordinates of the point <tt>point_expression</tt>.</li>
				2121	</ul></li>
				2122
				2123	<li>
				2124	<p>Example:</p>
				2125
				2126	<div class="source">
				2127	<div class="source">
				2128	<pre>use dataverse TinySocial;
				2129
				2130	let $point := create-point(2.3,5.0)
				2131	return {"x-coordinate": get-x($point), "y-coordinate": get-y($point)}
				2132	</pre></div></div></li>
				2133	</ul>
				2134
				2135	<ul>
				2136
				2137	<li>
				2138	<p>The expected result is:</p>
				2139
				2140	<div class="source">
				2141	<div class="source">
				2142	<pre>{ "x-coordinate": 2.3d, "y-coordinate": 5.0d }
				2143	</pre></div></div></li>
				2144	</ul></div>
				2145	<div class="section">
				2146	<h3><a name="get-points"></a>get-points</h3>
				2147
				2148	<ul>
				2149
				2150	<li>
				2151	<p>Syntax:</p>
				2152
				2153	<div class="source">
				2154	<div class="source">
				2155	<pre>get-points(spatial_expression)
				2156	</pre></div></div></li>
				2157
				2158	<li>
				2159	<p>Returns an ordered list of the points forming the spatial object <tt>spatial_expression</tt>.</p></li>
				2160
				2161	<li>Arguments:
				2162
				2163	<ul>
				2164
				2165	<li><tt>spatial_expression</tt> : A <tt>point</tt>, <tt>line</tt>, <tt>rectangle</tt>, <tt>circle</tt>, or <tt>polygon</tt>.</li>
				2166	</ul></li>
				2167
				2168	<li>Return Value:
				2169
				2170	<ul>
				2171
				2172	<li>An <tt>OrderedList</tt> of the points forming the spatial object <tt>spatial_expression</tt>.</li>
				2173	</ul></li>
				2174
				2175	<li>
				2176	<p>Example:</p>
				2177
				2178	<div class="source">
				2179	<div class="source">
				2180	<pre>use dataverse TinySocial;
				2181
				2182	let $line := create-line(create-point(100.6,99.4), create-point(-72.0,-76.9))
				2183	let $rectangle := create-rectangle(create-point(9.2,49.0), create-point(77.8,111.1))
				2184	let $polygon := create-polygon([1.0,1.0,2.0,2.0,3.0,3.0,4.0,4.0])
				2185	let $line_list := get-points($line)
				2186	let $rectangle_list := get-points($rectangle)
				2187	let $polygon_list := get-points($polygon)
				2188	return {"line-first-point": $line_list[0], "line-second-point": $line_list[1], "rectangle-left-bottom-point": $rectangle_list[0], "rectangle-top-upper-point": $rectangle_list[1], "polygon-first-point": $polygon_list[0], "polygon-second-point": $polygon_list[1], "polygon-third-point": $polygon_list[2], "polygon-forth-point": $polygon_list[3]}
				2189	</pre></div></div></li>
				2190	</ul>
				2191
				2192	<ul>
				2193
				2194	<li>
				2195	<p>The expected result is:</p>
				2196
				2197	<div class="source">
				2198	<div class="source">
				2199	<pre>{ "line-first-point": point("100.6,99.4"), "line-second-point": point("-72.0,-76.9"), "rectangle-left-bottom-point": point("9.2,49.0"), "rectangle-top-upper-point": point("77.8,111.1"), "polygon-first-point": point("1.0,1.0"), "polygon-second-point": point("2.0,2.0"), "polygon-third-point": point("3.0,3.0"), "polygon-forth-point": point("4.0,4.0") }
				2200	</pre></div></div></li>
				2201	</ul></div>
				2202	<div class="section">
				2203	<h3><a name="get-centerget-radius"></a>get-center/get-radius</h3>
				2204
				2205	<ul>
				2206
				2207	<li>
				2208	<p>Syntax:</p>
				2209
				2210	<div class="source">
				2211	<div class="source">
				2212	<pre>get-center(circle_expression) or get-radius(circle_expression)
				2213	</pre></div></div></li>
				2214
				2215	<li>
				2216	<p>Returns the center and the radius of a circle <tt>circle_expression</tt>, respectively.</p></li>
				2217
				2218	<li>Arguments:
				2219
				2220	<ul>
				2221
				2222	<li><tt>circle_expression</tt> : A <tt>circle</tt>.</li>
				2223	</ul></li>
				2224
				2225	<li>Return Value:
				2226
				2227	<ul>
				2228
				2229	<li>A <tt>point</tt> or <tt>double</tt>, represent the center or radius of the circle <tt>circle_expression</tt>.</li>
				2230	</ul></li>
				2231
				2232	<li>
				2233	<p>Example:</p>
				2234
				2235	<div class="source">
				2236	<div class="source">
				2237	<pre>use dataverse TinySocial;
				2238
				2239	let $circle := create-circle(create-point(6.0,3.0), 1.0)
				2240	return {"circle-radius": get-radius($circle), "circle-center": get-center($circle)}
				2241	</pre></div></div></li>
				2242	</ul>
				2243
				2244	<ul>
				2245
				2246	<li>
				2247	<p>The expected result is:</p>
				2248
				2249	<div class="source">
				2250	<div class="source">
				2251	<pre>{ "circle-radius": 1.0d, "circle-center": point("6.0,3.0") }
				2252	</pre></div></div></li>
				2253	</ul></div>
				2254	<div class="section">
				2255	<h3><a name="spatial-distance"></a>spatial-distance</h3>
				2256
				2257	<ul>
				2258
				2259	<li>
				2260	<p>Syntax:</p>
				2261
				2262	<div class="source">
				2263	<div class="source">
				2264	<pre>spatial-distance(point_expression1, point_expression2)
				2265	</pre></div></div></li>
				2266
				2267	<li>
				2268	<p>Returns the Euclidean distance between <tt>point_expression1</tt> and <tt>point_expression2</tt>.</p></li>
				2269
				2270	<li>Arguments:
				2271
				2272	<ul>
				2273
				2274	<li><tt>point_expression1</tt> : A <tt>point</tt>.</li>
				2275
				2276	<li><tt>point_expression2</tt> : A <tt>point</tt>.</li>
				2277	</ul></li>
				2278
				2279	<li>Return Value:
				2280
				2281	<ul>
				2282
				2283	<li>A <tt>double</tt> as the Euclidean distance between <tt>point_expression1</tt> and <tt>point_expression2</tt>.</li>
				2284	</ul></li>
				2285
				2286	<li>
				2287	<p>Example:</p>
				2288
				2289	<div class="source">
				2290	<div class="source">
				2291	<pre>use dataverse TinySocial;
				2292
				2293	for $t in dataset('TweetMessages')
				2294	let $d := spatial-distance($t.sender-location, create-point(30.0,70.0))
				2295	return {"point": $t.sender-location, "distance": $d}
				2296	</pre></div></div></li>
				2297	</ul>
				2298
				2299	<ul>
				2300
				2301	<li>
				2302	<p>The expected result is:</p>
				2303
				2304	<div class="source">
				2305	<div class="source">
				2306	<pre>{ "point": point("47.44,80.65"), "distance": 20.434678857275934d }
				2307	{ "point": point("29.15,76.53"), "distance": 6.585089217315132d }
				2308	{ "point": point("37.59,68.42"), "distance": 7.752709203884797d }
				2309	{ "point": point("24.82,94.63"), "distance": 25.168816023007512d }
				2310	{ "point": point("32.84,67.14"), "distance": 4.030533463451212d }
				2311	{ "point": point("29.72,75.8"), "distance": 5.806754687430835d }
				2312	{ "point": point("39.28,70.48"), "distance": 9.292405501268227d }
				2313	{ "point": point("40.09,92.69"), "distance": 24.832321679617472d }
				2314	{ "point": point("47.51,83.99"), "distance": 22.41250097601782d }
				2315	{ "point": point("36.21,72.6"), "distance": 6.73231758015024d }
				2316	{ "point": point("46.05,93.34"), "distance": 28.325926286707734d }
				2317	{ "point": point("36.86,74.62"), "distance": 8.270671073135482d }
				2318	</pre></div></div></li>
				2319	</ul></div>
				2320	<div class="section">
				2321	<h3><a name="spatial-area"></a>spatial-area</h3>
				2322
				2323	<ul>
				2324
				2325	<li>
				2326	<p>Syntax:</p>
				2327
				2328	<div class="source">
				2329	<div class="source">
				2330	<pre>spatial-area(spatial_2d_expression)
				2331	</pre></div></div></li>
				2332
				2333	<li>
				2334	<p>Returns the spatial area of <tt>spatial_2d_expression</tt>.</p></li>
				2335
				2336	<li>Arguments:
				2337
				2338	<ul>
				2339
				2340	<li><tt>spatial_2d_expression</tt> : A <tt>rectangle</tt>, <tt>circle</tt>, or <tt>polygon</tt>.</li>
				2341	</ul></li>
				2342
				2343	<li>Return Value:
				2344
				2345	<ul>
				2346
				2347	<li>A <tt>double</tt> representing the area of <tt>spatial_2d_expression</tt>.</li>
				2348	</ul></li>
				2349
				2350	<li>
				2351	<p>Example:</p>
				2352
				2353	<div class="source">
				2354	<div class="source">
				2355	<pre>use dataverse TinySocial;
				2356
				2357	let $circleArea := spatial-area(create-circle(create-point(0.0,0.0), 5.0))
				2358	return {"Area":$circleArea}
				2359	</pre></div></div></li>
				2360	</ul>
				2361
				2362	<ul>
				2363
				2364	<li>
				2365	<p>The expected result is:</p>
				2366
				2367	<div class="source">
				2368	<div class="source">
				2369	<pre>{ "Area": 78.53981625d }
				2370	</pre></div></div></li>
				2371	</ul></div>
				2372	<div class="section">
				2373	<h3><a name="spatial-intersect"></a>spatial-intersect</h3>
				2374
				2375	<ul>
				2376
				2377	<li>
				2378	<p>Syntax:</p>
				2379
				2380	<div class="source">
				2381	<div class="source">
				2382	<pre>spatial-intersect(spatial_expression1, spatial_expression2)
				2383	</pre></div></div></li>
				2384
				2385	<li>
				2386	<p>Checks whether <tt>@arg1</tt> and <tt>@arg2</tt> spatially intersect each other.</p></li>
				2387
				2388	<li>Arguments:
				2389
				2390	<ul>
				2391
				2392	<li><tt>spatial_expression1</tt> : A <tt>point</tt>, <tt>line</tt>, <tt>rectangle</tt>, <tt>circle</tt>, or <tt>polygon</tt>.</li>
				2393
				2394	<li><tt>spatial_expression2</tt> : A <tt>point</tt>, <tt>line</tt>, <tt>rectangle</tt>, <tt>circle</tt>, or <tt>polygon</tt>.</li>
				2395	</ul></li>
				2396
				2397	<li>Return Value:
				2398
				2399	<ul>
				2400
				2401	<li>A <tt>boolean</tt> representing whether <tt>spatial_expression1</tt> and <tt>spatial_expression2</tt> spatially overlap with each other.</li>
				2402	</ul></li>
				2403
				2404	<li>
				2405	<p>Example:</p>
				2406
				2407	<div class="source">
				2408	<div class="source">
				2409	<pre>use dataverse TinySocial;
				2410
				2411	for $t in dataset('TweetMessages')
				2412	where spatial-intersect($t.sender-location, create-rectangle(create-point(30.0,70.0), create-point(40.0,80.0)))
				2413	return $t
				2414	</pre></div></div></li>
				2415	</ul>
				2416
				2417	<ul>
				2418
				2419	<li>
				2420	<p>The expected result is:</p>
				2421
				2422	<div class="source">
				2423	<div class="source">
				2424	<pre>{ "tweetid": "4", "user": { "screen-name": "NathanGiesen@211", "lang": "en", "friends_count": 39339, "statuses_count": 473, "name": "Nathan Giesen", "followers_count": 49416 }, "sender-location": point("39.28,70.48"), "send-time": datetime("2011-12-26T10:10:00.000Z"), "referred-topics": {{ "sprint", "voice-command" }}, "message-text": " like sprint the voice-command is mind-blowing:)" }
				2425	{ "tweetid": "7", "user": { "screen-name": "ChangEwing_573", "lang": "en", "friends_count": 182, "statuses_count": 394, "name": "Chang Ewing", "followers_count": 32136 }, "sender-location": point("36.21,72.6"), "send-time": datetime("2011-08-25T10:10:00.000Z"), "referred-topics": {{ "samsung", "platform" }}, "message-text": " like samsung the platform is good" }
				2426	{ "tweetid": "9", "user": { "screen-name": "NathanGiesen@211", "lang": "en", "friends_count": 39339, "statuses_count": 473, "name": "Nathan Giesen", "followers_count": 49416 }, "sender-location": point("36.86,74.62"), "send-time": datetime("2012-07-21T10:10:00.000Z"), "referred-topics": {{ "verizon", "voicemail-service" }}, "message-text": " love verizon its voicemail-service is awesome" }
				2427	</pre></div></div></li>
				2428	</ul></div>
				2429	<div class="section">
				2430	<h3><a name="spatial-cell"></a>spatial-cell</h3>
				2431
				2432	<ul>
				2433
				2434	<li>
				2435	<p>Syntax:</p>
				2436
				2437	<div class="source">
				2438	<div class="source">
				2439	<pre>spatial-cell(point_expression1, point_expression2, x_increment, y_increment)
				2440	</pre></div></div></li>
				2441
				2442	<li>
				2443	<p>Returns the grid cell that <tt>point_expression1</tt> belongs to.</p></li>
				2444
				2445	<li>Arguments:
				2446
				2447	<ul>
				2448
				2449	<li><tt>point_expression1</tt> : A <tt>point</tt> representing the point of interest that its grid cell will be returned.</li>
				2450
				2451	<li><tt>point_expression2</tt> : A <tt>point</tt> representing the origin of the grid.</li>
				2452
				2453	<li><tt>x_increment</tt> : A <tt>double</tt>, represents X increments.</li>
				2454
				2455	<li><tt>y_increment</tt> : A <tt>double</tt>, represents Y increments.</li>
				2456	</ul></li>
				2457
				2458	<li>Return Value:
				2459
				2460	<ul>
				2461
				2462	<li>A <tt>rectangle</tt> representing the grid cell that <tt>point_expression1</tt> belongs to.</li>
				2463	</ul></li>
				2464
				2465	<li>
				2466	<p>Example:</p>
				2467
				2468	<div class="source">
				2469	<div class="source">
				2470	<pre>use dataverse TinySocial;
				2471
				2472	for $t in dataset('TweetMessages')
				2473	group by $c := spatial-cell($t.sender-location, create-point(20.0,50.0), 5.5, 6.0) with $t
				2474	let $num := count($t)
				2475	return { "cell": $c, "count": $num}
				2476	</pre></div></div></li>
				2477	</ul>
				2478
				2479	<ul>
				2480
				2481	<li>
				2482	<p>The expected result is:</p>
				2483
				2484	<div class="source">
				2485	<div class="source">
				2486	<pre>{ "cell": rectangle("20.0,92.0 25.5,98.0"), "count": 1i64 }
				2487	{ "cell": rectangle("25.5,74.0 31.0,80.0"), "count": 2i64 }
				2488	{ "cell": rectangle("31.0,62.0 36.5,68.0"), "count": 1i64 }
				2489	{ "cell": rectangle("31.0,68.0 36.5,74.0"), "count": 1i64 }
				2490	{ "cell": rectangle("36.5,68.0 42.0,74.0"), "count": 2i64 }
				2491	{ "cell": rectangle("36.5,74.0 42.0,80.0"), "count": 1i64 }
				2492	{ "cell": rectangle("36.5,92.0 42.0,98.0"), "count": 1i64 }
				2493	{ "cell": rectangle("42.0,80.0 47.5,86.0"), "count": 1i64 }
				2494	{ "cell": rectangle("42.0,92.0 47.5,98.0"), "count": 1i64 }
				2495	{ "cell": rectangle("47.5,80.0 53.0,86.0"), "count": 1i64 }
				2496	</pre></div></div></li>
				2497	</ul></div></div>
				2498	<div class="section">
				2499	<h2><a name="Similarity_Functions_Back_to_TOC"></a><a name="SimilarityFunctions" id="SimilarityFunctions">Similarity Functions</a> <font size="4"><a href="#toc">[Back to TOC]</a></font></h2>
				2500	<p>AsterixDB supports queries with different similarity functions, including <a class="externalLink" href="http://en.wikipedia.org/wiki/Levenshtein_distance">edit distance</a> and <a class="externalLink" href="https://en.wikipedia.org/wiki/Jaccard_index">Jaccard</a>.</p>
				2501	<div class="section">
				2502	<h3><a name="edit-distance"></a>edit-distance</h3>
				2503
				2504	<ul>
				2505
				2506	<li>
				2507	<p>Syntax:</p>
				2508
				2509	<div class="source">
				2510	<div class="source">
				2511	<pre>edit-distance(expression1, expression2)
				2512	</pre></div></div></li>
				2513
				2514	<li>
				2515	<p>Returns the edit distance of <tt>expression1</tt> and <tt>expression2</tt>.</p></li>
				2516
				2517	<li>Arguments:
				2518
				2519	<ul>
				2520
				2521	<li><tt>expression1</tt> : A <tt>string</tt> or a homogeneous <tt>OrderedList</tt> of a comparable item type.</li>
				2522
				2523	<li><tt>expression2</tt> : The same type as <tt>expression1</tt>.</li>
				2524	</ul></li>
				2525
				2526	<li>Return Value:
				2527
				2528	<ul>
				2529
				2530	<li>An <tt>int64</tt> that represents the edit distance between <tt>expression1</tt> and <tt>expression2</tt>.</li>
				2531	</ul></li>
				2532
				2533	<li>Note: An <a href="similarity.html#UsingIndexesToSupportSimilarityQueries">n-gram index</a> can be utilized for this function.</li>
				2534
				2535	<li>
				2536	<p>Example:</p>
				2537
				2538	<div class="source">
				2539	<div class="source">
				2540	<pre>use dataverse TinySocial;
				2541
				2542	for $user in dataset('FacebookUsers')
				2543	let $ed := edit-distance($user.name, "Suzanna Tilson")
				2544	where $ed <= 2
				2545	return $user
				2546	</pre></div></div></li>
				2547	</ul>
				2548
				2549	<ul>
				2550
				2551	<li>
				2552	<p>The expected result is:</p>
				2553
				2554	<div class="source">
				2555	<div class="source">
				2556	<pre>{
				2557	"id": 7, "alias": "Suzanna", "name": "SuzannaTillson", "user-since": datetime("2012-08-07T10:10:00.000Z"), "friend-ids": {{ 6 }},
				2558	"employment": [ { "organization-name": "Labzatron", "start-date": date("2011-04-19"), "end-date": null } ]
				2559	}
				2560	</pre></div></div></li>
				2561	</ul></div>
				2562	<div class="section">
				2563	<h3><a name="edit-distance-check"></a>edit-distance-check</h3>
				2564
				2565	<ul>
				2566
				2567	<li>
				2568	<p>Syntax:</p>
				2569
				2570	<div class="source">
				2571	<div class="source">
				2572	<pre>edit-distance-check(expression1, expression2, threshold)
				2573	</pre></div></div></li>
				2574
				2575	<li>
				2576	<p>Checks whether <tt>expression1</tt> and <tt>expression2</tt> have an <a class="externalLink" href="http://en.wikipedia.org/wiki/Levenshtein_distance">edit distance</a> within a given threshold. The “check” version of edit distance is faster than the “non-check” version because the former can detect whether two items satisfy a given threshold using early-termination techniques, as opposed to computing their real distance. Although possible, it is not necessary for the user to write queries using the “check” versions explicitly, since a rewrite rule can perform an appropriate transformation from a “non-check” version to a “check” version.</p></li>
				2577
				2578	<li>
				2579	<p>Arguments:</p>
				2580
				2581	<ul>
				2582
				2583	<li><tt>expression1</tt> : A <tt>string</tt> or a homogeneous <tt>OrderedList</tt> of a comparable item type.</li>
				2584
				2585	<li><tt>expression2</tt> : The same type as <tt>expression1</tt>.</li>
				2586
				2587	<li><tt>threshold</tt> : An <tt>int64</tt> that represents the distance threshold.</li>
				2588	</ul></li>
				2589
				2590	<li>Return Value:
				2591
				2592	<ul>
				2593
				2594	<li>An <tt>OrderedList</tt> with two items:
				2595
				2596	<ul>
				2597
				2598	<li>The first item contains a <tt>boolean</tt> value representing whether <tt>expression1</tt> and <tt>expression2</tt> are similar.</li>
				2599
				2600	<li>The second item contains an <tt>int64</tt> that represents the edit distance of <tt>expression1</tt> and <tt>expression2</tt> if it is within the threshold, or 0 otherwise.</li>
				2601	</ul></li>
				2602	</ul></li>
				2603
				2604	<li>Note: An <a href="similarity.html#UsingIndexesToSupportSimilarityQueries">n-gram index</a> can be utilized for this function.</li>
				2605
				2606	<li>
				2607	<p>Example:</p>
				2608
				2609	<div class="source">
				2610	<div class="source">
				2611	<pre>use dataverse TinySocial;
				2612
				2613	for $user in dataset('FacebookUsers')
				2614	let $ed := edit-distance-check($user.name, "Suzanna Tilson", 2)
				2615	where $ed[0]
				2616	return $ed[1]
				2617	</pre></div></div></li>
				2618	</ul>
				2619
				2620	<ul>
				2621
				2622	<li>
				2623	<p>The expected result is:</p>
				2624
				2625	<div class="source">
				2626	<div class="source">
				2627	<pre>2
				2628	</pre></div></div></li>
				2629	</ul></div>
				2630	<div class="section">
				2631	<h3><a name="edit-distance-contains"></a>edit-distance-contains</h3>
				2632
				2633	<ul>
				2634
				2635	<li>Syntax:</li>
				2636	</ul>
				2637	<p>edit-distance-contains(expression1, expression2, threshold)</p>
				2638
				2639	<ul>
				2640
				2641	<li>
				2642	<p>Checks whether <tt>expression1</tt> contains <tt>expression2</tt> with an <a class="externalLink" href="http://en.wikipedia.org/wiki/Levenshtein_distance">edit distance</a> within a given threshold.</p></li>
				2643
				2644	<li>
				2645	<p>Arguments:</p>
				2646
				2647	<ul>
				2648
				2649	<li><tt>expression1</tt> : A <tt>string</tt> or a homogeneous <tt>OrderedList</tt> of a comparable item type.</li>
				2650
				2651	<li><tt>expression2</tt> : The same type as <tt>expression1</tt>.</li>
				2652
				2653	<li><tt>threshold</tt> : An <tt>int32</tt> that represents the distance threshold.</li>
				2654	</ul></li>
				2655
				2656	<li>Return Value:
				2657
				2658	<ul>
				2659
				2660	<li>An <tt>OrderedList</tt> with two items:
				2661
				2662	<ul>
				2663
				2664	<li>The first item contains a <tt>boolean</tt> value representing whether <tt>expression1</tt> can contain <tt>expression2</tt>.</li>
				2665
				2666	<li>The second item contains an <tt>int32</tt> that represents the required edit distance for <tt>expression1</tt> to contain <tt>expression2</tt> if the first item is true.</li>
				2667	</ul></li>
				2668	</ul></li>
				2669
				2670	<li>Note: An <a href="similarity.html#UsingIndexesToSupportSimilarityQueries">n-gram index</a> can be utilized for this function.</li>
				2671
				2672	<li>
				2673	<p>Example:</p>
				2674
				2675	<div class="source">
				2676	<div class="source">
				2677	<pre>let $i := edit-distance-contains("happy","hapr",2)
				2678	return $i;
				2679	</pre></div></div></li>
				2680	</ul>
				2681
				2682	<ul>
				2683
				2684	<li>
				2685	<p>The expected result is:</p>
				2686
				2687	<div class="source">
				2688	<div class="source">
				2689	<pre>[ true, 1 ]
				2690	</pre></div></div></li>
				2691	</ul></div>
				2692	<div class="section">
				2693	<h3><a name="similarity-jaccard"></a>similarity-jaccard</h3>
				2694
				2695	<ul>
				2696
				2697	<li>
				2698	<p>Syntax:</p>
				2699
				2700	<div class="source">
				2701	<div class="source">
				2702	<pre>similarity-jaccard(list_expression1, list_expression2)
				2703	</pre></div></div></li>
				2704
				2705	<li>
				2706	<p>Returns the <a class="externalLink" href="http://en.wikipedia.org/wiki/Jaccard_index">Jaccard similarity</a> of <tt>list_expression1</tt> and <tt>list_expression2</tt>.</p></li>
				2707
				2708	<li>Arguments:
				2709
				2710	<ul>
				2711
				2712	<li><tt>list_expression1</tt> : An <tt>UnorderedList</tt> or <tt>OrderedList</tt>.</li>
				2713
				2714	<li><tt>list_expression2</tt> : An <tt>UnorderedList</tt> or <tt>OrderedList</tt>.</li>
				2715	</ul></li>
				2716
				2717	<li>Return Value:
				2718
				2719	<ul>
				2720
				2721	<li>A <tt>float</tt> that represents the Jaccard similarity of <tt>list_expression1</tt> and <tt>list_expression2</tt>.</li>
				2722	</ul></li>
				2723
				2724	<li>Note: A <a href="similarity.html#UsingIndexesToSupportSimilarityQueries">keyword index</a> can be utilized for this function.</li>
				2725
				2726	<li>
				2727	<p>Example:</p>
				2728
				2729	<div class="source">
				2730	<div class="source">
				2731	<pre>use dataverse TinySocial;
				2732
				2733	for $user in dataset('FacebookUsers')
				2734	let $sim := similarity-jaccard($user.friend-ids, [1,5,9,10])
				2735	where $sim >= 0.6f
				2736	return $user
				2737	</pre></div></div></li>
				2738	</ul>
				2739
				2740	<ul>
				2741
				2742	<li>
				2743	<p>The expected result is:</p>
				2744
				2745	<div class="source">
				2746	<div class="source">
				2747	<pre>{
				2748	"id": 3, "alias": "Emory", "name": "EmoryUnk", "user-since": datetime("2012-07-10T10:10:00.000Z"), "friend-ids": {{ 1, 5, 8, 9 }},
				2749	"employment": [ { "organization-name": "geomedia", "start-date": date("2010-06-17"), "end-date": date("2010-01-26") } ]
				2750	}
				2751	{
				2752	"id": 10, "alias": "Bram", "name": "BramHatch", "user-since": datetime("2010-10-16T10:10:00.000Z"), "friend-ids": {{ 1, 5, 9 }},
				2753	"employment": [ { "organization-name": "physcane", "start-date": date("2007-06-05"), "end-date": date("2011-11-05") } ]
				2754	}
				2755	</pre></div></div></li>
				2756	</ul></div>
				2757	<div class="section">
				2758	<h3><a name="similarity-jaccard-check"></a>similarity-jaccard-check</h3>
				2759
				2760	<ul>
				2761
				2762	<li>
				2763	<p>Syntax:</p>
				2764
				2765	<div class="source">
				2766	<div class="source">
				2767	<pre>similarity-jaccard-check(list_expression1, list_expression2, threshold)
				2768	</pre></div></div></li>
				2769
				2770	<li>
				2771	<p>Checks whether <tt>list_expression1</tt> and <tt>list_expression2</tt> have a <a class="externalLink" href="http://en.wikipedia.org/wiki/Jaccard_index">Jaccard similarity</a> greater than or equal to threshold. Again, the “check” version of Jaccard is faster than the “non-check” version.</p></li>
				2772
				2773	<li>
				2774	<p>Arguments:</p>
				2775
				2776	<ul>
				2777
				2778	<li><tt>list_expression1</tt> : An <tt>UnorderedList</tt> or <tt>OrderedList</tt>.</li>
				2779
				2780	<li><tt>list_expression2</tt> : An <tt>UnorderedList</tt> or <tt>OrderedList</tt>.</li>
				2781
				2782	<li><tt>threshold</tt> : A <tt>float</tt> that represents the similarity threshold.</li>
				2783	</ul></li>
				2784
				2785	<li>Return Value:
				2786
				2787	<ul>
				2788
				2789	<li>An <tt>OrderedList</tt> with two items:</li>
				2790
				2791	<li>The first item contains a <tt>boolean</tt> value representing whether <tt>list_expression1</tt> and <tt>list_expression2</tt> are similar.</li>
				2792
				2793	<li>The second item contains a <tt>float</tt> that represents the Jaccard similarity of <tt>list_expression1</tt> and <tt>list_expression2</tt> if it is greater than or equal to the threshold, or 0 otherwise.</li>
				2794	</ul></li>
				2795
				2796	<li>Note: A <a href="similarity.html#UsingIndexesToSupportSimilarityQueries">keyword index</a> can be utilized for this function.</li>
				2797
				2798	<li>
				2799	<p>Example:</p>
				2800
				2801	<div class="source">
				2802	<div class="source">
				2803	<pre>use dataverse TinySocial;
				2804
				2805	for $user in dataset('FacebookUsers')
				2806	let $sim := similarity-jaccard-check($user.friend-ids, [1,5,9,10], 0.6f)
				2807	where $sim[0]
				2808	return $sim[1]
				2809	</pre></div></div></li>
				2810	</ul>
				2811
				2812	<ul>
				2813
				2814	<li>
				2815	<p>The expected result is:</p>
				2816
				2817	<div class="source">
				2818	<div class="source">
				2819	<pre>0.75f
				2820	1.0f
				2821	</pre></div></div></li>
				2822	</ul></div>
				2823	<div class="section">
				2824	<h3><a name="Similarity_Operator_"></a>Similarity Operator ~=</h3>
				2825
				2826	<ul>
				2827
				2828	<li>“<tt>~=</tt>” is syntactic sugar for expressing a similarity condition with a given similarity threshold.</li>
				2829
				2830	<li>The similarity function and threshold for “<tt>~=</tt>” are controlled via “set” directives.</li>
				2831
				2832	<li>The “<tt>~=</tt>” operator returns a <tt>boolean</tt> value that represents whether the operands are similar.</li>
				2833
				2834	<li>
				2835	<p>Example for Jaccard similarity:</p>
				2836
				2837	<div class="source">
				2838	<div class="source">
				2839	<pre>use dataverse TinySocial;
				2840
				2841	set simfunction "jaccard";
				2842	set simthreshold "0.6f";
				2843
				2844	for $user in dataset('FacebookUsers')
				2845	where $user.friend-ids ~= [1,5,9,10]
				2846	return $user
				2847	</pre></div></div></li>
				2848	</ul>
				2849
				2850	<ul>
				2851
				2852	<li>
				2853	<p>The expected result is:</p>
				2854
				2855	<div class="source">
				2856	<div class="source">
				2857	<pre>{
				2858	"id": 3, "alias": "Emory", "name": "EmoryUnk", "user-since": datetime("2012-07-10T10:10:00.000Z"), "friend-ids": {{ 1, 5, 8, 9 }},
				2859	"employment": [ { "organization-name": "geomedia", "start-date": date("2010-06-17"), "end-date": date("2010-01-26") } ]
				2860	}
				2861	{
				2862	"id": 10, "alias": "Bram", "name": "BramHatch", "user-since": datetime("2010-10-16T10:10:00.000Z"), "friend-ids": {{ 1, 5, 9 }},
				2863	"employment": [ { "organization-name": "physcane", "start-date": date("2007-06-05"), "end-date": date("2011-11-05") } ]
				2864	}
				2865	</pre></div></div></li>
				2866	</ul>
				2867
				2868	<ul>
				2869
				2870	<li>
				2871	<p>Example for edit-distance similarity:</p>
				2872
				2873	<div class="source">
				2874	<div class="source">
				2875	<pre>use dataverse TinySocial;
				2876
				2877	set simfunction "edit-distance";
				2878	set simthreshold "2";
				2879
				2880	for $user in dataset('FacebookUsers')
				2881	where $user.name ~= "Suzanna Tilson"
				2882	return $user
				2883	</pre></div></div></li>
				2884	</ul>
				2885
				2886	<ul>
				2887
				2888	<li>
				2889	<p>The expected output is:</p>
				2890
				2891	<div class="source">
				2892	<div class="source">
				2893	<pre>{
				2894	"id": 7, "alias": "Suzanna", "name": "SuzannaTillson", "user-since": datetime("2012-08-07T10:10:00.000Z"), "friend-ids": {{ 6 }},
				2895	"employment": [ { "organization-name": "Labzatron", "start-date": date("2011-04-19"), "end-date": null } ]
				2896	}
				2897	</pre></div></div></li>
				2898	</ul></div></div>
				2899	<div class="section">
				2900	<h2><a name="Tokenizing_Functions_Back_to_TOC"></a><a name="TokenizingFunctions" id="TokenizingFunctions">Tokenizing Functions</a> <font size="4"><a href="#toc">[Back to TOC]</a></font></h2>
				2901	<div class="section">
				2902	<h3><a name="word-tokens"></a>word-tokens</h3>
				2903
				2904	<ul>
				2905
				2906	<li>
				2907	<p>Syntax:</p>
				2908
				2909	<div class="source">
				2910	<div class="source">
				2911	<pre>word-tokens(string_expression)
				2912	</pre></div></div></li>
				2913
				2914	<li>
				2915	<p>Returns a list of word tokens of <tt>string_expression</tt> using non-alphanumeric characters as delimiters.</p></li>
				2916
				2917	<li>Arguments:
				2918
				2919	<ul>
				2920
				2921	<li><tt>string_expression</tt> : A <tt>string</tt> that will be tokenized.</li>
				2922	</ul></li>
				2923
				2924	<li>Return Value:
				2925
				2926	<ul>
				2927
				2928	<li>An <tt>OrderedList</tt> of <tt>string</tt> word tokens.</li>
				2929	</ul></li>
				2930
				2931	<li>
				2932	<p>Example:</p>
				2933
				2934	<div class="source">
				2935	<div class="source">
				2936	<pre>use dataverse TinySocial;
				2937
				2938	for $t in dataset('TweetMessages')
				2939	let $tokens := word-tokens($t.message-text)
				2940	where $t.send-time >= datetime('2012-01-01T00:00:00')
				2941	return {
				2942	"tweetid": $t.tweetid,
				2943	"word-tokens": $tokens
				2944	}
				2945	</pre></div></div></li>
				2946	</ul>
				2947
				2948	<ul>
				2949
				2950	<li>
				2951	<p>The expected result is:</p>
				2952
				2953	<div class="source">
				2954	<div class="source">
				2955	<pre>{ "tweetid": "9", "word-tokens": [ "love", "verizon", "its", "voicemail", "service", "is", "awesome" ] }
				2956	</pre></div></div></li>
				2957	</ul>
				2958	<!-- ### hashed-word-tokens ###
				2959	* Syntax:
				2960
				2961	hashed-word-tokens(string_expression)
				2962
				2963	* Returns a list of hashed word tokens of `string_expression`.
				2964	* Arguments:
				2965	* `string_expression` : A `string` that will be tokenized.
				2966	* Return Value:
				2967	* An `OrderedList` of `int32` hashed tokens.
				2968
				2969	* Example:
				2970
				2971	use dataverse TinySocial;
				2972
				2973	for $t in dataset('TweetMessages')
				2974	let $tokens := hashed-word-tokens($t.message-text)
				2975	where $t.send-time >= datetime('2012-01-01T00:00:00')
				2976	return {
				2977	"tweetid": $t.tweetid,
				2978	"hashed-word-tokens": $tokens
				2979	}
				2980
				2981
				2982	* The expected result is:
				2983
				2984	{ "tweetid": "9", "hashed-word-tokens": [ -1217719622, -447857469, -1884722688, -325178649, 210976949, 285049676, 1916743959 ] }
				2985
				2986
				2987	### counthashed-word-tokens ###
				2988	* Syntax:
				2989
				2990	counthashed-word-tokens(string_expression)
				2991
				2992	* Returns a list of hashed word tokens of `string_expression`. The hashing mechanism gives duplicate tokens different hash values, based on the occurrence count of that token.
				2993	* Arguments:
				2994	* `string_expression` : A `String` that will be tokenized.
				2995	* Return Value:
				2996	* An `OrderedList` of `Int32` hashed tokens.
				2997	* Example:
				2998
				2999	use dataverse TinySocial;
				3000
				3001	for $t in dataset('TweetMessages')
				3002	let $tokens := counthashed-word-tokens($t.message-text)
				3003	where $t.send-time >= datetime('2012-01-01T00:00:00')
				3004	return {
				3005	"tweetid": $t.tweetid,
				3006	"counthashed-word-tokens": $tokens
				3007	}
				3008
				3009
				3010	* The expected result is:
				3011
				3012	{ "tweetid": "9", "counthashed-word-tokens": [ -1217719622, -447857469, -1884722688, -325178649, 210976949, 285049676, 1916743959 ] }
				3013
				3014
				3015	### gram-tokens ###
				3016	* Syntax:
				3017
				3018	gram-tokens(string_expression, gram_length, boolean_expression)
				3019
				3020	* Returns a list of gram tokens of `string_expression`, which can be obtained by scanning the characters using a sliding window of a fixed length.
				3021	* Arguments:
				3022	* `string_expression` : A `String` that will be tokenized.
				3023	* `gram_length` : An `Int32` as the length of grams.
				3024	* `boolean_expression` : A `Boolean` value to indicate whether to generate additional grams by pre- and postfixing `string_expression` with special characters.
				3025	* Return Value:
				3026	* An `OrderedList` of String gram tokens.
				3027
				3028	* Example:
				3029
				3030	use dataverse TinySocial;
				3031
				3032	for $t in dataset('TweetMessages')
				3033	let $tokens := gram-tokens($t.message-text, 3, true)
				3034	where $t.send-time >= datetime('2012-01-01T00:00:00')
				3035	return {
				3036	"tweetid": $t.tweetid,
				3037	"gram-tokens": $tokens
				3038	}
				3039
				3040
				3041	* The expected result is:
				3042
				3043	{
				3044	"tweetid": "9",
				3045	"gram-tokens": [ "## ", "# l", " lo", "lov", "ove", "ve ", "e v", " ve", "ver", "eri", "riz", "izo", "zon", "on ", "n i", " it", "its", "ts ", "s v", " vo", "voi", "oic", "ice",
				3046	"cem", "ema", "mai", "ail", "il-", "l-s", "-se", "ser", "erv", "rvi", "vic", "ice", "ce ", "e i", " is", "is ", "s a", " aw", "awe", "wes", "eso", "som", "ome", "me$", "e$$" ]
				3047	}
				3048
				3049
				3050	### hashed-gram-tokens ###
				3051	* Syntax:
				3052
				3053	hashed-gram-tokens(string_expression, gram_length, boolean_expression)
				3054
				3055	* Returns a list of hashed gram tokens of `string_expression`.
				3056	* Arguments:
				3057	* `string_expression` : A `String` that will be tokenized.
				3058	* `gram_length` : An `Int32` as the length of grams.
				3059	* `boolean_expression` : A `Boolean` to indicate whether to generate additional grams by pre- and postfixing `string_expression` with special characters.
				3060	* Return Value:
				3061	* An `OrderedList` of `Int32` hashed gram tokens.
				3062
				3063	* Example:
				3064
				3065	use dataverse TinySocial;
				3066
				3067	for $t in dataset('TweetMessages')
				3068	let $tokens := hashed-gram-tokens($t.message-text, 3, true)
				3069	where $t.send-time >= datetime('2012-01-01T00:00:00')
				3070	return {
				3071	"tweetid": $t.tweetid,
				3072	"hashed-gram-tokens": $tokens
				3073	}
				3074
				3075
				3076	* The expected result is:
				3077
				3078	{
				3079	"tweetid": "9",
				3080	"hashed-gram-tokens": [ 40557178, -2002241593, 161665899, -856104603, -500544946, 693410611, 395674299, -1015235909, 1115608337, 1187999872, -31006095, -219180466, -1676061637,
				3081	1040194153, -1339307841, -1527110163, -1884722688, -179148713, -431014627, -1789789823, -1209719926, 684519765, -486734513, 1734740619, -1971673751, -932421915, -2064668066,
				3082	-937135958, -790946468, -69070309, 1561601454, 26169001, -160734571, 1330043462, -486734513, -18796768, -470303314, 113421364, 1615760212, 1688217556, 1223719184, 536568131,
				3083	1682609873, 2935161, -414769471, -1027490137, 1602276102, 1050490461 ]
				3084	}
				3085
				3086
				3087	### counthashed-gram-tokens ###
				3088	* Syntax:
				3089
				3090	counthashed-gram-tokens(string_expression, gram_length, boolean_expression)
				3091
				3092	* Returns a list of hashed gram tokens of `string_expression`. The hashing mechanism gives duplicate tokens different hash values, based on the occurrence count of that token.
				3093	* Arguments:
				3094	* `string_expression` : A `String` that will be tokenized.
				3095	* `gram_length` : An `Int32`, length of grams to generate.
				3096	* `boolean_expression` : A `Boolean`, whether to generate additional grams by pre- and postfixing `string_expression` with special characters.
				3097	* Return Value:
				3098	* An `OrderedList` of `Int32` hashed gram tokens.
				3099
				3100	* Example:
				3101
				3102	use dataverse TinySocial;
				3103
				3104	for $t in dataset('TweetMessages')
				3105	let $tokens := counthashed-gram-tokens($t.message-text, 3, true)
				3106	where $t.send-time >= datetime('2012-01-01T00:00:00')
				3107	return {
				3108	"tweetid": $t.tweetid,
				3109	"counthashed-gram-tokens": $tokens
				3110	}
				3111
				3112
				3113	* The expected result is:
				3114
				3115	{
				3116	"tweetid": "9",
				3117	"counthashed-gram-tokens": [ 40557178, -2002241593, 161665899, -856104603, -500544946, 693410611, 395674299, -1015235909, 1115608337, 1187999872, -31006095, -219180466, -1676061637,
				3118	1040194153, -1339307841, -1527110163, -1884722688, -179148713, -431014627, -1789789823, -1209719926, 684519765, -486734513, 1734740619, -1971673751, -932421915, -2064668066, -937135958,
				3119	-790946468, -69070309, 1561601454, 26169001, -160734571, 1330043462, -486734512, -18796768, -470303314, 113421364, 1615760212, 1688217556, 1223719184, 536568131, 1682609873, 2935161,
				3120	-414769471, -1027490137, 1602276102, 1050490461 ]
				3121	} --></div></div>
				3122	<div class="section">
				3123	<h2><a name="Temporal_Functions_Back_to_TOC"></a><a name="TemporalFunctions" id="TemporalFunctions">Temporal Functions</a> <font size="4"><a href="#toc">[Back to TOC]</a></font></h2>
				3124	<div class="section">
				3125	<h3><a name="get-yearget-monthget-dayget-hourget-minuteget-secondget-millisecond"></a>get-year/get-month/get-day/get-hour/get-minute/get-second/get-millisecond</h3>
				3126
				3127	<ul>
				3128
				3129	<li>
				3130	<p>Syntax:</p>
				3131
				3132	<div class="source">
				3133	<div class="source">
				3134	<pre>get-year/get-month/get-day/get-hour/get-minute/get-second/get-millisecond(temporal_expression)
				3135	</pre></div></div></li>
				3136
				3137	<li>
				3138	<p>Accessors for accessing fields in a temporal value</p></li>
				3139
				3140	<li>Arguments:
				3141
				3142	<ul>
				3143
				3144	<li><tt>temporal_expression</tt> : a temporal value represented as one of the following types: <tt>date</tt>, <tt>datetime</tt>, <tt>time</tt>, and <tt>duration</tt>.</li>
				3145	</ul></li>
				3146
				3147	<li>Return Value:
				3148
				3149	<ul>
				3150
				3151	<li>An <tt>int64</tt> value representing the field to be extracted.</li>
				3152	</ul></li>
				3153
				3154	<li>
				3155	<p>Example:</p>
				3156
				3157	<div class="source">
				3158	<div class="source">
				3159	<pre>let $c1 := date("2010-10-30")
				3160	let $c2 := datetime("1987-11-19T23:49:23.938")
				3161	let $c3 := time("12:23:34.930+07:00")
				3162	let $c4 := duration("P3Y73M632DT49H743M3948.94S")
				3163
				3164	return {"year": get-year($c1), "month": get-month($c2), "day": get-day($c1), "hour": get-hour($c3), "min": get-minute($c4), "second": get-second($c2), "ms": get-millisecond($c4)}
				3165	</pre></div></div></li>
				3166	</ul>
				3167
				3168	<ul>
				3169
				3170	<li>
				3171	<p>The expected result is:</p>
				3172
				3173	<div class="source">
				3174	<div class="source">
				3175	<pre>{ "year": 2010, "month": 11, "day": 30, "hour": 5, "min": 28, "second": 23, "ms": 94 }
				3176	</pre></div></div></li>
				3177	</ul></div>
				3178	<div class="section">
				3179	<h3><a name="adjust-datetime-for-timezone"></a>adjust-datetime-for-timezone</h3>
				3180
				3181	<ul>
				3182
				3183	<li>
				3184	<p>Syntax:</p>
				3185
				3186	<div class="source">
				3187	<div class="source">
				3188	<pre>adjust-datetime-for-timezone(datetime_expression, string_expression)
				3189	</pre></div></div></li>
				3190
				3191	<li>
				3192	<p>Adjusts the given datetime <tt>datetime_expression</tt> by applying the timezone information <tt>string_expression</tt>.</p></li>
				3193
				3194	<li>Arguments:
				3195
				3196	<ul>
				3197
				3198	<li><tt>datetime_expression</tt> : A <tt>datetime</tt> value to be adjusted.</li>
				3199
				3200	<li><tt>string_expression</tt> : A <tt>string</tt> representing the timezone information.</li>
				3201	</ul></li>
				3202
				3203	<li>Return Value:
				3204
				3205	<ul>
				3206
				3207	<li>A <tt>string</tt> value representing the new datetime after being adjusted by the timezone information.</li>
				3208	</ul></li>
				3209
				3210	<li>
				3211	<p>Example:</p>
				3212
				3213	<div class="source">
				3214	<div class="source">
				3215	<pre>use dataverse TinySocial;
				3216
				3217	for $i in dataset('TweetMessages')
				3218	return {"adjusted-send-time": adjust-datetime-for-timezone($i.send-time, "+08:00"), "message": $i.message-text}
				3219	</pre></div></div></li>
				3220	</ul>
				3221
				3222	<ul>
				3223
				3224	<li>
				3225	<p>The expected result is:</p>
				3226
				3227	<div class="source">
				3228	<div class="source">
				3229	<pre>{ "adjusted-send-time": "2008-04-26T18:10:00.000+08:00", "message": " love t-mobile its customization is good:)" }
				3230	{ "adjusted-send-time": "2010-05-13T18:10:00.000+08:00", "message": " like verizon its shortcut-menu is awesome:)" }
				3231	{ "adjusted-send-time": "2006-11-04T18:10:00.000+08:00", "message": " like motorola the speed is good:)" }
				3232	{ "adjusted-send-time": "2011-12-26T18:10:00.000+08:00", "message": " like sprint the voice-command is mind-blowing:)" }
				3233	{ "adjusted-send-time": "2006-08-04T18:10:00.000+08:00", "message": " can't stand motorola its speed is terrible:(" }
				3234	{ "adjusted-send-time": "2010-05-07T18:10:00.000+08:00", "message": " like iphone the voice-clarity is good:)" }
				3235	{ "adjusted-send-time": "2011-08-25T18:10:00.000+08:00", "message": " like samsung the platform is good" }
				3236	{ "adjusted-send-time": "2005-10-14T18:10:00.000+08:00", "message": " like t-mobile the shortcut-menu is awesome:)" }
				3237	{ "adjusted-send-time": "2012-07-21T18:10:00.000+08:00", "message": " love verizon its voicemail-service is awesome" }
				3238	{ "adjusted-send-time": "2008-01-26T18:10:00.000+08:00", "message": " hate verizon its voice-clarity is OMG:(" }
				3239	{ "adjusted-send-time": "2008-03-09T18:10:00.000+08:00", "message": " can't stand iphone its platform is terrible" }
				3240	{ "adjusted-send-time": "2010-02-13T18:10:00.000+08:00", "message": " like samsung the voice-command is amazing:)" }
				3241	</pre></div></div></li>
				3242	</ul></div>
				3243	<div class="section">
				3244	<h3><a name="adjust-time-for-timezone"></a>adjust-time-for-timezone</h3>
				3245
				3246	<ul>
				3247
				3248	<li>
				3249	<p>Syntax:</p>
				3250
				3251	<div class="source">
				3252	<div class="source">
				3253	<pre>adjust-time-for-timezone(time_expression, string_expression)
				3254	</pre></div></div></li>
				3255
				3256	<li>
				3257	<p>Adjusts the given time <tt>time_expression</tt> by applying the timezone information <tt>string_expression</tt>.</p></li>
				3258
				3259	<li>Arguments:
				3260
				3261	<ul>
				3262
				3263	<li><tt>time_expression</tt> : A <tt>time</tt> value to be adjusted.</li>
				3264
				3265	<li><tt>string_expression</tt> : A <tt>string</tt> representing the timezone information.</li>
				3266	</ul></li>
				3267
				3268	<li>Return Value:
				3269
				3270	<ul>
				3271
				3272	<li>A <tt>string</tt> value representing the new time after being adjusted by the timezone information.</li>
				3273	</ul></li>
				3274
				3275	<li>
				3276	<p>Example:</p>
				3277
				3278	<div class="source">
				3279	<div class="source">
				3280	<pre>use dataverse TinySocial;
				3281
				3282	for $i in dataset('TweetMessages')
				3283	return {"adjusted-send-time": adjust-time-for-timezone(time-from-datetime($i.send-time), "+08:00"), "message": $i.message-text}
				3284	</pre></div></div></li>
				3285	</ul>
				3286
				3287	<ul>
				3288
				3289	<li>
				3290	<p>The expected result is:</p>
				3291
				3292	<div class="source">
				3293	<div class="source">
				3294	<pre>{ "adjusted-send-time": "18:10:00.000+08:00", "message": " love t-mobile its customization is good:)" }
				3295	{ "adjusted-send-time": "18:10:00.000+08:00", "message": " like verizon its shortcut-menu is awesome:)" }
				3296	{ "adjusted-send-time": "18:10:00.000+08:00", "message": " like motorola the speed is good:)" }
				3297	{ "adjusted-send-time": "18:10:00.000+08:00", "message": " like sprint the voice-command is mind-blowing:)" }
				3298	{ "adjusted-send-time": "18:10:00.000+08:00", "message": " can't stand motorola its speed is terrible:(" }
				3299	{ "adjusted-send-time": "18:10:00.000+08:00", "message": " like iphone the voice-clarity is good:)" }
				3300	{ "adjusted-send-time": "18:10:00.000+08:00", "message": " like samsung the platform is good" }
				3301	{ "adjusted-send-time": "18:10:00.000+08:00", "message": " like t-mobile the shortcut-menu is awesome:)" }
				3302	{ "adjusted-send-time": "18:10:00.000+08:00", "message": " love verizon its voicemail-service is awesome" }
				3303	{ "adjusted-send-time": "18:10:00.000+08:00", "message": " hate verizon its voice-clarity is OMG:(" }
				3304	{ "adjusted-send-time": "18:10:00.000+08:00", "message": " can't stand iphone its platform is terrible" }
				3305	{ "adjusted-send-time": "18:10:00.000+08:00", "message": " like samsung the voice-command is amazing:)" }
				3306	</pre></div></div></li>
				3307	</ul></div>
				3308	<div class="section">
				3309	<h3><a name="calendar-duration-from-datetime"></a>calendar-duration-from-datetime</h3>
				3310
				3311	<ul>
				3312
				3313	<li>
				3314	<p>Syntax:</p>
				3315
				3316	<div class="source">
				3317	<div class="source">
				3318	<pre>calendar-duration-from-datetime(datetime_expression, duration_expression)
				3319	</pre></div></div></li>
				3320
				3321	<li>
				3322	<p>Gets a user-friendly representation of the duration <tt>duration_expression</tt> based on the given datetime <tt>datetime_expression</tt>.</p></li>
				3323
				3324	<li>Arguments:
				3325
				3326	<ul>
				3327
				3328	<li><tt>datetime_expression</tt> : A <tt>datetime</tt> value to be used as the reference time point.</li>
				3329
				3330	<li><tt>duration_expression</tt> : A <tt>duration</tt> value to be converted.</li>
				3331	</ul></li>
				3332
				3333	<li>Return Value:
				3334
				3335	<ul>
				3336
				3337	<li>A <tt>duration</tt> value with the duration as <tt>duration_expression</tt> but with a user-friendly representation.</li>
				3338	</ul></li>
				3339
				3340	<li>
				3341	<p>Example:</p>
				3342
				3343	<div class="source">
				3344	<div class="source">
				3345	<pre>use dataverse TinySocial;
				3346
				3347	for $i in dataset('TweetMessages')
				3348	where $i.send-time > datetime("2011-01-01T00:00:00")
				3349	return {"since-2011": subtract-datetime($i.send-time, datetime("2011-01-01T00:00:00")), "since-2011-user-friendly": calendar-duration-from-datetime($i.send-time, subtract-datetime($i.send-time, datetime("2011-01-01T00:00:00")))}
				3350	</pre></div></div></li>
				3351	</ul>
				3352
				3353	<ul>
				3354
				3355	<li>
				3356	<p>The expected result is:</p>
				3357
				3358	<div class="source">
				3359	<div class="source">
				3360	<pre>{ "since-2011": duration("P359DT10H10M"), "since-2011-user-friendly": duration("P11M23DT10H10M") }
				3361	{ "since-2011": duration("P236DT10H10M"), "since-2011-user-friendly": duration("P7M23DT10H10M") }
				3362	{ "since-2011": duration("P567DT10H10M"), "since-2011-user-friendly": duration("P1Y6M18DT10H10M") }
				3363	</pre></div></div></li>
				3364	</ul></div>
				3365	<div class="section">
				3366	<h3><a name="get-year-month-durationget-day-time-duration"></a>get-year-month-duration/get-day-time-duration</h3>
				3367
				3368	<ul>
				3369
				3370	<li>
				3371	<p>Syntax:</p>
				3372
				3373	<div class="source">
				3374	<div class="source">
				3375	<pre>get-year-month-duration/get-day-time-duration(duration_expression)
				3376	</pre></div></div></li>
				3377
				3378	<li>
				3379	<p>Extracts the correct <tt>duration</tt> subtype from <tt>duration_expression</tt>.</p></li>
				3380
				3381	<li>Arguments:
				3382
				3383	<ul>
				3384
				3385	<li><tt>duration_expression</tt> : A <tt>duration</tt> value to be converted.</li>
				3386	</ul></li>
				3387
				3388	<li>Return Value:
				3389
				3390	<ul>
				3391
				3392	<li>A <tt>year-month-duration</tt> value or a <tt>day-time-duration</tt> value.</li>
				3393	</ul></li>
				3394
				3395	<li>
				3396	<p>Example:</p>
				3397
				3398	<div class="source">
				3399	<div class="source">
				3400	<pre>let $i := get-year-month-duration(duration("P12M50DT10H"))
				3401	return $i;
				3402	</pre></div></div></li>
				3403	</ul>
				3404
				3405	<ul>
				3406
				3407	<li>
				3408	<p>The expected result is:</p>
				3409
				3410	<div class="source">
				3411	<div class="source">
				3412	<pre>year-month-duration("P1Y")
				3413	</pre></div></div></li>
				3414	</ul></div>
				3415	<div class="section">
				3416	<h3><a name="months-from-year-month-durationmilliseconds-from-day-time-duration"></a>months-from-year-month-duration/milliseconds-from-day-time-duration</h3>
				3417
				3418	<ul>
				3419
				3420	<li>
				3421	<p>Syntax:</p>
				3422
				3423	<div class="source">
				3424	<div class="source">
				3425	<pre>months-from-year-month-duration/milliseconds-from-day-time-duration(duration_expression)
				3426	</pre></div></div></li>
				3427
				3428	<li>
				3429	<p>Extracts the number of months or the number of milliseconds from the <tt>duration</tt> subtype.</p></li>
				3430
				3431	<li>Arguments:
				3432
				3433	<ul>
				3434
				3435	<li><tt>duration_expression</tt> : A <tt>duration</tt> of the correct subtype.</li>
				3436	</ul></li>
				3437
				3438	<li>Return Value:
				3439
				3440	<ul>
				3441
				3442	<li>An <tt>int64</tt> representing the number or months/milliseconds.</li>
				3443	</ul></li>
				3444
				3445	<li>
				3446	<p>Example:</p>
				3447
				3448	<div class="source">
				3449	<div class="source">
				3450	<pre>let $i := months-from-year-month-duration(get-year-month-duration(duration("P5Y7MT50M")))
				3451	return $i;
				3452	</pre></div></div></li>
				3453	</ul>
				3454
				3455	<ul>
				3456
				3457	<li>
				3458	<p>The expected result is:</p>
				3459
				3460	<div class="source">
				3461	<div class="source">
				3462	<pre>67
				3463	</pre></div></div></li>
				3464	</ul></div>
				3465	<div class="section">
				3466	<h3><a name="duration-from-monthsduration-from-ms"></a>duration-from-months/duration-from-ms</h3>
				3467
				3468	<ul>
				3469
				3470	<li>
				3471	<p>Syntax:</p>
				3472
				3473	<div class="source">
				3474	<div class="source">
				3475	<pre>duration-from-months/duration-from-ms(number_expression)
				3476	</pre></div></div></li>
				3477
				3478	<li>
				3479	<p>Creates a <tt>duration</tt> from <tt>number_expression</tt>.</p></li>
				3480
				3481	<li>Arguments:
				3482
				3483	<ul>
				3484
				3485	<li><tt>number_expression</tt> : An <tt>int64</tt> representing the number of months/milliseconds</li>
				3486	</ul></li>
				3487
				3488	<li>Return Value:
				3489
				3490	<ul>
				3491
				3492	<li>A <tt>duration</tt> containing <tt>number_expression</tt> value for months/milliseconds</li>
				3493	</ul></li>
				3494
				3495	<li>
				3496	<p>Example:</p>
				3497
				3498	<div class="source">
				3499	<div class="source">
				3500	<pre>let $i := duration-from-months(8)
				3501	return $i;
				3502	</pre></div></div></li>
				3503
				3504	<li>
				3505	<p>The expected result is:</p>
				3506
				3507	<div class="source">
				3508	<div class="source">
				3509	<pre>duration("P8M")
				3510	</pre></div></div></li>
				3511	</ul></div>
				3512	<div class="section">
				3513	<h3><a name="duration-from-interval"></a>duration-from-interval</h3>
				3514
				3515	<ul>
				3516
				3517	<li>
				3518	<p>Syntax:</p>
				3519
				3520	<div class="source">
				3521	<div class="source">
				3522	<pre>duration-from-interval(interval_expression)
				3523	</pre></div></div></li>
				3524
				3525	<li>
				3526	<p>Creates a <tt>duration</tt> from <tt>interval_expression</tt>.</p></li>
				3527
				3528	<li>Arguments:
				3529
				3530	<ul>
				3531
				3532	<li><tt>interval_expression</tt> : An <tt>interval</tt> value</li>
				3533	</ul></li>
				3534
				3535	<li>Return Value:
				3536
				3537	<ul>
				3538
				3539	<li>A <tt>duration</tt> repesenting the time in the <tt>interval_expression</tt></li>
				3540	</ul></li>
				3541
				3542	<li>
				3543	<p>Example:</p>
				3544
				3545	<div class="source">
				3546	<div class="source">
				3547	<pre>let $itv1 := interval-from-date("2010-10-30", "2010-12-21")
				3548	let $itv2 := interval-from-datetime("2012-06-26T01:01:01.111", "2012-07-27T02:02:02.222")
				3549	let $itv3 := interval-from-time("12:32:38", "20:29:20")
				3550
				3551	return { "dr1" : duration-from-interval($itv1),
				3552	"dr2" : duration-from-interval($itv2),
				3553	"dr3" : duration-from-interval($itv3),
				3554	"dr4" : duration-from-interval(null) }
				3555	</pre></div></div></li>
				3556
				3557	<li>
				3558	<p>The expected result is:</p>
				3559
				3560	<div class="source">
				3561	<div class="source">
				3562	<pre>{ "dr1": day-time-duration("P52D"),
				3563	"dr2": day-time-duration("P31DT1H1M1.111S"),
				3564	"dr3": day-time-duration("PT7H56M42S"),
				3565	"dr4": null }
				3566	</pre></div></div></li>
				3567	</ul></div>
				3568	<div class="section">
				3569	<h3><a name="current-date"></a>current-date</h3>
				3570
				3571	<ul>
				3572
				3573	<li>
				3574	<p>Syntax:</p>
				3575
				3576	<div class="source">
				3577	<div class="source">
				3578	<pre>current-date()
				3579	</pre></div></div></li>
				3580
				3581	<li>
				3582	<p>Gets the current date.</p></li>
				3583
				3584	<li>Arguments: None</li>
				3585
				3586	<li>Return Value:
				3587
				3588	<ul>
				3589
				3590	<li>A <tt>date</tt> value of the date when the function is called.</li>
				3591	</ul></li>
				3592	</ul></div>
				3593	<div class="section">
				3594	<h3><a name="current-time"></a>current-time</h3>
				3595
				3596	<ul>
				3597
				3598	<li>
				3599	<p>Syntax:</p>
				3600
				3601	<div class="source">
				3602	<div class="source">
				3603	<pre>current-time()
				3604	</pre></div></div></li>
				3605
				3606	<li>
				3607	<p>Get the current time</p></li>
				3608
				3609	<li>Arguments: None</li>
				3610
				3611	<li>Return Value:
				3612
				3613	<ul>
				3614
				3615	<li>A <tt>time</tt> value of the time when the function is called.</li>
				3616	</ul></li>
				3617	</ul></div>
				3618	<div class="section">
				3619	<h3><a name="current-datetime"></a>current-datetime</h3>
				3620
				3621	<ul>
				3622
				3623	<li>
				3624	<p>Syntax:</p>
				3625
				3626	<div class="source">
				3627	<div class="source">
				3628	<pre>current-datetime()
				3629	</pre></div></div></li>
				3630
				3631	<li>
				3632	<p>Get the current datetime</p></li>
				3633
				3634	<li>Arguments: None</li>
				3635
				3636	<li>Return Value:
				3637
				3638	<ul>
				3639
				3640	<li>A <tt>datetime</tt> value of the datetime when the function is called.</li>
				3641	</ul></li>
				3642
				3643	<li>
				3644	<p>Example:</p>
				3645
				3646	<div class="source">
				3647	<div class="source">
				3648	<pre>{"current-date": current-date(),
				3649	"current-time": current-time(),
				3650	"current-datetime": current-datetime()}
				3651	</pre></div></div></li>
				3652	</ul>
				3653
				3654	<ul>
				3655
				3656	<li>
				3657	<p>The expected result is:</p>
				3658
				3659	<div class="source">
				3660	<div class="source">
				3661	<pre>{ "current-date": date("2013-04-06"),
				3662	"current-time": time("00:48:44.093Z"),
				3663	"current-datetime": datetime("2013-04-06T00:48:44.093Z") }
				3664	</pre></div></div></li>
				3665	</ul></div>
				3666	<div class="section">
				3667	<h3><a name="get-date-from-datetime"></a>get-date-from-datetime</h3>
				3668
				3669	<ul>
				3670
				3671	<li>
				3672	<p>Syntax:</p>
				3673
				3674	<div class="source">
				3675	<div class="source">
				3676	<pre>get-date-from-datetime(datetime_expression)
				3677	</pre></div></div></li>
				3678
				3679	<li>
				3680	<p>Gets the date value from the given datetime value <tt>datetime_expression</tt>.</p></li>
				3681
				3682	<li>Arguments:
				3683
				3684	<ul>
				3685
				3686	<li><tt>datetime_expression</tt>: A <tt>datetime</tt> value to be extracted from.</li>
				3687	</ul></li>
				3688
				3689	<li>Return Value:
				3690
				3691	<ul>
				3692
				3693	<li>A <tt>date</tt> value from the datetime.</li>
				3694	</ul></li>
				3695	</ul></div>
				3696	<div class="section">
				3697	<h3><a name="get-time-from-datetime"></a>get-time-from-datetime</h3>
				3698
				3699	<ul>
				3700
				3701	<li>
				3702	<p>Syntax:</p>
				3703
				3704	<div class="source">
				3705	<div class="source">
				3706	<pre>get-time-from-datetime(datetime_expression)
				3707	</pre></div></div></li>
				3708
				3709	<li>
				3710	<p>Get the time value from the given datetime value <tt>datetime_expression</tt></p></li>
				3711
				3712	<li>Arguments:
				3713
				3714	<ul>
				3715
				3716	<li><tt>datetime_expression</tt>: A <tt>datetime</tt> value to be extracted from</li>
				3717	</ul></li>
				3718
				3719	<li>Return Value:
				3720
				3721	<ul>
				3722
				3723	<li>A <tt>time</tt> value from the datetime.</li>
				3724	</ul></li>
				3725
				3726	<li>
				3727	<p>Example:</p>
				3728
				3729	<div class="source">
				3730	<div class="source">
				3731	<pre>use dataverse TinySocial;
				3732
				3733	for $i in dataset('TweetMessages')
				3734	where $i.send-time > datetime("2011-01-01T00:00:00")
				3735	return {"send-date": get-date-from-datetime($i.send-time), "send-time": get-time-from-datetime($i.send-time)}
				3736	</pre></div></div></li>
				3737	</ul>
				3738
				3739	<ul>
				3740
				3741	<li>
				3742	<p>The expected result is:</p>
				3743
				3744	<div class="source">
				3745	<div class="source">
				3746	<pre>{ "send-date": date("2011-12-26"), "send-time": time("10:10:00.000Z") }
				3747	{ "send-date": date("2011-08-25"), "send-time": time("10:10:00.000Z") }
				3748	{ "send-date": date("2012-07-21"), "send-time": time("10:10:00.000Z") }
				3749	</pre></div></div></li>
				3750	</ul></div>
				3751	<div class="section">
				3752	<h3><a name="day-of-week"></a>day-of-week</h3>
				3753
				3754	<ul>
				3755
				3756	<li>
				3757	<p>Syntax:</p>
				3758
				3759	<div class="source">
				3760	<div class="source">
				3761	<pre>day-of-week(date_expression)
				3762	</pre></div></div></li>
				3763
				3764	<li>
				3765	<p>Finds the day of the week for a given date (1-7)</p></li>
				3766
				3767	<li>Arguments:
				3768
				3769	<ul>
				3770
				3771	<li><tt>date_expression</tt>: A <tt>date</tt> value (Can also be a <tt>datetime</tt>)</li>
				3772	</ul></li>
				3773
				3774	<li>Return Value:
				3775
				3776	<ul>
				3777
				3778	<li>An <tt>int8</tt> representing the day of the week (1-7)</li>
				3779	</ul></li>
				3780
				3781	<li>
				3782	<p>Example:</p>
				3783
				3784	<div class="source">
				3785	<div class="source">
				3786	<pre>let $i := day-of-week( datetime("2012-12-30T12:12:12.039Z"))
				3787	return $i;
				3788	</pre></div></div></li>
				3789	</ul>
				3790
				3791	<ul>
				3792
				3793	<li>
				3794	<p>The expected result is:</p>
				3795
				3796	<div class="source">
				3797	<div class="source">
				3798	<pre>7
				3799	</pre></div></div></li>
				3800	</ul></div>
				3801	<div class="section">
				3802	<h3><a name="date-from-unix-time-in-days"></a>date-from-unix-time-in-days</h3>
				3803
				3804	<ul>
				3805
				3806	<li>
				3807	<p>Syntax:</p>
				3808
				3809	<div class="source">
				3810	<div class="source">
				3811	<pre>date-from-unix-time-in-days(numeric_expression)
				3812	</pre></div></div></li>
				3813
				3814	<li>
				3815	<p>Gets a date representing the time after <tt>numeric_expression</tt> days since 1970-01-01.</p></li>
				3816
				3817	<li>Arguments:
				3818
				3819	<ul>
				3820
				3821	<li><tt>numeric_expression</tt>: A <tt>int8</tt>/<tt>int16</tt>/<tt>int32</tt>/<tt>int64</tt> value representing the number of days.</li>
				3822	</ul></li>
				3823
				3824	<li>Return Value:
				3825
				3826	<ul>
				3827
				3828	<li>A <tt>date</tt> value as the time after <tt>numeric_expression</tt> days since 1970-01-01.</li>
				3829	</ul></li>
				3830	</ul></div>
				3831	<div class="section">
				3832	<h3><a name="datetime-from-unix-time-in-ms"></a>datetime-from-unix-time-in-ms</h3>
				3833
				3834	<ul>
				3835
				3836	<li>
				3837	<p>Syntax:</p>
				3838
				3839	<div class="source">
				3840	<div class="source">
				3841	<pre>datetime-from-unix-time-in-ms(numeric_expression)
				3842	</pre></div></div></li>
				3843
				3844	<li>
				3845	<p>Gets a datetime representing the time after <tt>numeric_expression</tt> milliseconds since 1970-01-01T00:00:00Z.</p></li>
				3846
				3847	<li>Arguments:
				3848
				3849	<ul>
				3850
				3851	<li><tt>numeric_expression</tt>: A <tt>int8</tt>/<tt>int16</tt>/<tt>int32</tt>/<tt>int64</tt> value representing the number of milliseconds.</li>
				3852	</ul></li>
				3853
				3854	<li>Return Value:
				3855
				3856	<ul>
				3857
				3858	<li>A <tt>datetime</tt> value as the time after <tt>numeric_expression</tt> milliseconds since 1970-01-01T00:00:00Z.</li>
				3859	</ul></li>
				3860	</ul></div>
				3861	<div class="section">
				3862	<h3><a name="datetime-from-unix-time-in-secs"></a>datetime-from-unix-time-in-secs</h3>
				3863
				3864	<ul>
				3865
				3866	<li>
				3867	<p>Syntax:</p>
				3868
				3869	<div class="source">
				3870	<div class="source">
				3871	<pre>datetime-from-unix-time-in-secs(numeric_expression)
				3872	</pre></div></div></li>
				3873
				3874	<li>
				3875	<p>Gets a datetime representing the time after <tt>numeric_expression</tt> seconds since 1970-01-01T00:00:00Z.</p></li>
				3876
				3877	<li>Arguments:
				3878
				3879	<ul>
				3880
				3881	<li><tt>numeric_expression</tt>: A <tt>int8</tt>/<tt>int16</tt>/<tt>int32</tt>/<tt>int64</tt> value representing the number of seconds.</li>
				3882	</ul></li>
				3883
				3884	<li>Return Value:
				3885
				3886	<ul>
				3887
				3888	<li>A <tt>datetime</tt> value as the time after <tt>numeric_expression</tt> seconds since 1970-01-01T00:00:00Z.</li>
				3889	</ul></li>
				3890	</ul></div>
				3891	<div class="section">
				3892	<h3><a name="datetime-from-date-time"></a>datetime-from-date-time</h3>
				3893
				3894	<ul>
				3895
				3896	<li>Syntax:</li>
				3897	</ul>
				3898	<p>datetime-from-date-time(date_expression,time_expression)</p>
				3899
				3900	<ul>
				3901
				3902	<li>Gets a datetime representing the combination of <tt>date_expression</tt> and <tt>time_expression</tt>
				3903
				3904	<ul>
				3905
				3906	<li>Arguments:</li>
				3907
				3908	<li><tt>date_expression</tt>: A <tt>date</tt> value</li>
				3909
				3910	<li><tt>time_expression</tt> A <tt>time</tt> value</li>
				3911	</ul></li>
				3912
				3913	<li>Return Value:
				3914
				3915	<ul>
				3916
				3917	<li>A <tt>datetime</tt> value by combining <tt>date_expression</tt> and <tt>time_expression</tt></li>
				3918	</ul></li>
				3919	</ul></div>
				3920	<div class="section">
				3921	<h3><a name="time-from-unix-time-in-ms"></a>time-from-unix-time-in-ms</h3>
				3922
				3923	<ul>
				3924
				3925	<li>
				3926	<p>Syntax:</p>
				3927
				3928	<div class="source">
				3929	<div class="source">
				3930	<pre>time-from-unix-time-in-ms(numeric_expression)
				3931	</pre></div></div></li>
				3932
				3933	<li>
				3934	<p>Gets a time representing the time after <tt>numeric_expression</tt> milliseconds since 00:00:00.000Z.</p></li>
				3935
				3936	<li>Arguments:
				3937
				3938	<ul>
				3939
				3940	<li><tt>numeric_expression</tt>: A <tt>int8</tt>/<tt>int16</tt>/<tt>int32</tt>/<tt>int64</tt> value representing the number of milliseconds.</li>
				3941	</ul></li>
				3942
				3943	<li>Return Value:
				3944
				3945	<ul>
				3946
				3947	<li>A <tt>time</tt> value as the time after <tt>numeric_expression</tt> milliseconds since 00:00:00.000Z.</li>
				3948	</ul></li>
				3949
				3950	<li>
				3951	<p>Example:</p>
				3952
				3953	<div class="source">
				3954	<div class="source">
				3955	<pre>use dataverse TinySocial;
				3956
				3957	let $d := date-from-unix-time-in-days(15800)
				3958	let $dt := datetime-from-unix-time-in-ms(1365139700000)
				3959	let $t := time-from-unix-time-in-ms(3748)
				3960	return {"date": $d, "datetime": $dt, "time": $t}
				3961	</pre></div></div></li>
				3962	</ul>
				3963
				3964	<ul>
				3965
				3966	<li>
				3967	<p>The expected result is:</p>
				3968
				3969	<div class="source">
				3970	<div class="source">
				3971	<pre>{ "date": date("2013-04-05"), "datetime": datetime("2013-04-05T05:28:20.000Z"), "time": time("00:00:03.748Z") }
				3972	</pre></div></div></li>
				3973	</ul></div>
				3974	<div class="section">
				3975	<h3><a name="parse-dateparse-timeparse-datetime"></a>parse-date/parse-time/parse-datetime</h3>
				3976
				3977	<ul>
				3978
				3979	<li>Syntax:</li>
				3980	</ul>
				3981	<p>parse-date/parse-time/parse-datetime(date_expression,formatting_expression)</p>
				3982
				3983	<ul>
				3984
				3985	<li>Creates a <tt>date/time/date-time</tt> value by treating <tt>date_expression</tt> with formatting <tt>formatting_expression</tt></li>
				3986
				3987	<li>Arguments:
				3988
				3989	<ul>
				3990
				3991	<li><tt>date_expression</tt>: A <tt>string</tt> value representing the <tt>date/time/datetime</tt>.</li>
				3992
				3993	<li><tt>formatting_expression</tt> A <tt>string</tt> value providing the formatting for <tt>date_expression</tt>.Characters used to create date expression:</li>
				3994
				3995	<li><tt>h</tt> hours</li>
				3996
				3997	<li><tt>m</tt> minutes</li>
				3998
				3999	<li><tt>s</tt> seconds</li>
				4000
				4001	<li><tt>n</tt> milliseconds</li>
				4002
				4003	<li><tt>a</tt> am/pm</li>
				4004
				4005	<li><tt>z</tt> timezone</li>
				4006
				4007	<li><tt>Y</tt> year</li>
				4008
				4009	<li><tt>M</tt> month</li>
				4010
				4011	<li><tt>D</tt> day</li>
				4012
				4013	<li><tt>W</tt> weekday</li>
				4014
				4015	<li><tt>-</tt>, <tt>'</tt>, <tt>/</tt>, <tt>.</tt>, <tt>,</tt>, <tt>T</tt> seperators for both time and date</li>
				4016	</ul></li>
				4017
				4018	<li>Return Value:
				4019
				4020	<ul>
				4021
				4022	<li>A <tt>date/time/date-time</tt> value corresponding to <tt>date_expression</tt></li>
				4023	</ul></li>
				4024
				4025	<li>
				4026	<p>Example:</p>
				4027
				4028	<div class="source">
				4029	<div class="source">
				4030	<pre>let $i := parse-time("30:30","m:s")
				4031	return $i;
				4032	</pre></div></div></li>
				4033
				4034	<li>
				4035	<p>The expected result is:</p>
				4036
				4037	<div class="source">
				4038	<div class="source">
				4039	<pre>time("00:30:30.000Z")
				4040	</pre></div></div></li>
				4041	</ul></div>
				4042	<div class="section">
				4043	<h3><a name="print-dateprint-timeprint-datetime"></a>print-date/print-time/print-datetime</h3>
				4044
				4045	<ul>
				4046
				4047	<li>Syntax:</li>
				4048	</ul>
				4049	<p>print-date/print-time/print-datetime(date_expression,formatting_expression)</p>
				4050
				4051	<ul>
				4052
				4053	<li>Creates a <tt>string</tt> representing a <tt>date/time/date-time</tt> value of the <tt>date_expression</tt> using the formatting <tt>formatting_expression</tt></li>
				4054
				4055	<li>Arguments:
				4056
				4057	<ul>
				4058
				4059	<li><tt>date_expression</tt>: A <tt>date/time/datetime</tt> value.</li>
				4060
				4061	<li><tt>formatting_expression</tt> A <tt>string</tt> value providing the formatting for <tt>date_expression</tt>. Characters used to create date expression:</li>
				4062
				4063	<li><tt>h</tt> hours</li>
				4064
				4065	<li><tt>m</tt> minutes</li>
				4066
				4067	<li><tt>s</tt> seconds</li>
				4068
				4069	<li><tt>n</tt> milliseconds</li>
				4070
				4071	<li><tt>a</tt> am/pm</li>
				4072
				4073	<li><tt>z</tt> timezone</li>
				4074
				4075	<li><tt>Y</tt> year</li>
				4076
				4077	<li><tt>M</tt> month</li>
				4078
				4079	<li><tt>D</tt> day</li>
				4080
				4081	<li><tt>W</tt> weekday</li>
				4082
				4083	<li><tt>-</tt>, <tt>'</tt>, <tt>/</tt>, <tt>.</tt>, <tt>,</tt>, <tt>T</tt> seperators for both time and date</li>
				4084	</ul></li>
				4085
				4086	<li>Return Value:
				4087
				4088	<ul>
				4089
				4090	<li>A <tt>string</tt> value corresponding to <tt>date_expression</tt></li>
				4091	</ul></li>
				4092
				4093	<li>
				4094	<p>Example:</p>
				4095
				4096	<div class="source">
				4097	<div class="source">
				4098	<pre>let $i := print-time(time("00:30:30.000Z"),"m:s")
				4099	return $i;
				4100	</pre></div></div></li>
				4101
				4102	<li>
				4103	<p>The expected result is:</p>
				4104
				4105	<div class="source">
				4106	<div class="source">
				4107	<pre>"30:30"
				4108	</pre></div></div></li>
				4109	</ul></div>
				4110	<div class="section">
				4111	<h3><a name="get-interval-start_get-interval-end"></a>get-interval-start, get-interval-end</h3>
				4112
				4113	<ul>
				4114
				4115	<li>
				4116	<p>Syntax:</p>
				4117
				4118	<div class="source">
				4119	<div class="source">
				4120	<pre>get-interval-start/get-interval-end(interval)
				4121	</pre></div></div></li>
				4122
				4123	<li>
				4124	<p>Gets the start/end of the given interval.</p></li>
				4125
				4126	<li>Arguments:
				4127
				4128	<ul>
				4129
				4130	<li><tt>interval</tt>: the interval to be accessed.</li>
				4131	</ul></li>
				4132
				4133	<li>Return Value:
				4134
				4135	<ul>
				4136
				4137	<li>A <tt>time</tt>, <tt>date</tt>, or <tt>datetime</tt> (depending on the time instances of the interval) representing the starting or ending time.</li>
				4138	</ul></li>
				4139
				4140	<li>
				4141	<p>Example:</p>
				4142
				4143	<div class="source">
				4144	<div class="source">
				4145	<pre>let $itv := interval-start-from-date("1984-01-01", "P1Y")
				4146	return {"start": get-interval-start($itv), "end": get-interval-end($itv)}
				4147	</pre></div></div></li>
				4148	</ul>
				4149
				4150	<ul>
				4151
				4152	<li>
				4153	<p>The expected result is:</p>
				4154
				4155	<div class="source">
				4156	<div class="source">
				4157	<pre>{ "start": date("1984-01-01"), "end": date("1985-01-01") }
				4158	</pre></div></div></li>
				4159	</ul></div>
				4160	<div class="section">
				4161	<h3><a name="get-interval-start-dateget-interval-start-datetimeget-interval-start-time_get-interval-end-dateget-interval-end-datetimeget-interval-end-time"></a>get-interval-start-date/get-interval-start-datetimeget-interval-start-time, get-interval-end-date/get-interval-end-datetime/get-interval-end-time</h3>
				4162
				4163	<ul>
				4164
				4165	<li>
				4166	<p>Syntax:</p>
				4167
				4168	<div class="source">
				4169	<div class="source">
				4170	<pre>get-interval-start-date/get-interval-start-datetime/get-interval-start-time/get-interval-end-date/get-interval-end-datetime/get-interval-end-time(interval)
				4171	</pre></div></div></li>
				4172
				4173	<li>
				4174	<p>Gets the start/end of the given interval for the specific date/datetime/time type.</p></li>
				4175
				4176	<li>Arguments:
				4177
				4178	<ul>
				4179
				4180	<li><tt>interval</tt>: the interval to be accessed.</li>
				4181	</ul></li>
				4182
				4183	<li>Return Value:
				4184
				4185	<ul>
				4186
				4187	<li>A <tt>time</tt>, <tt>date</tt>, or <tt>datetime</tt> (depending on the function) representing the starting or ending time.</li>
				4188	</ul></li>
				4189
				4190	<li>
				4191	<p>Example:</p>
				4192
				4193	<div class="source">
				4194	<div class="source">
				4195	<pre>let $itv1 := interval-start-from-date("1984-01-01", "P1Y")
				4196	let $itv2 := interval-start-from-datetime("1984-01-01T08:30:00.000", "P1Y1H")
				4197	let $itv3 := interval-start-from-time("08:30:00.000", "P1H")
				4198	return {"start": get-interval-start-date($itv1), "end": get-interval-end-date($itv1), "start": get-interval-start-datetime($itv2), "end": get-interval-end-datetime($itv2), "start": get-interval-start-time($itv3), "end": get-interval-end-time($itv3)}
				4199	</pre></div></div></li>
				4200	</ul>
				4201
				4202	<ul>
				4203
				4204	<li>
				4205	<p>The expected result is:</p>
				4206
				4207	<div class="source">
				4208	<div class="source">
				4209	<pre>{ "start": date("1984-01-01"), "end": date("1985-01-01"), "start": datetime("1984-01-01T08:30:00.000"), "end": datetime("1984-02-01T09:30:00.000"), "start": date("08:30:00.000"), "end": time("09:30:00.000") }
				4210	</pre></div></div></li>
				4211	</ul></div>
				4212	<div class="section">
				4213	<h3><a name="get-overlapping-interval"></a>get-overlapping-interval</h3>
				4214
				4215	<ul>
				4216
				4217	<li>
				4218	<p>Syntax:</p>
				4219
				4220	<div class="source">
				4221	<div class="source">
				4222	<pre>get-overlapping-interval(interval_expression_1, interval_expression_2)
				4223	</pre></div></div></li>
				4224
				4225	<li>
				4226	<p>Gets the start/end of the given interval for the specific date/datetime/time type.</p></li>
				4227
				4228	<li>Arguments:
				4229
				4230	<ul>
				4231
				4232	<li><tt>interval_expression_1</tt>: an <tt>interval</tt> value</li>
				4233
				4234	<li><tt>interval_expression_2</tt>: an <tt>interval</tt> value</li>
				4235	</ul></li>
				4236
				4237	<li>Return Value:
				4238
				4239	<ul>
				4240
				4241	<li>Returns an <tt>interval</tt> that is overlapping <tt>interval_expression_1</tt> and <tt>interval_expression_2</tt>. If <tt>interval_expression_1</tt> and <tt>interval_expression_2</tt> do not overlap <tt>null</tt> is returned. Note each interval must be of the same type.</li>
				4242	</ul></li>
				4243
				4244	<li>
				4245	<p>Example:</p>
				4246
				4247	<div class="source">
				4248	<div class="source">
				4249	<pre>{ "overlap1": get-overlapping-interval(interval-from-time(time("11:23:39"), time("18:27:19")), interval-from-time(time("12:23:39"), time("23:18:00"))),
				4250	"overlap2": get-overlapping-interval(interval-from-time(time("12:23:39"), time("18:27:19")), interval-from-time(time("07:19:39"), time("09:18:00"))),
				4251	"overlap3": get-overlapping-interval(interval-from-date(date("1980-11-30"), date("1999-09-09")), interval-from-date(date("2013-01-01"), date("2014-01-01"))),
				4252	"overlap4": get-overlapping-interval(interval-from-date(date("1980-11-30"), date("2099-09-09")), interval-from-date(date("2013-01-01"), date("2014-01-01"))),
				4253	"overlap5": get-overlapping-interval(interval-from-datetime(datetime("1844-03-03T11:19:39"), datetime("2000-10-30T18:27:19")), interval-from-datetime(datetime("1989-03-04T12:23:39"), datetime("2009-10-10T23:18:00"))),
				4254	"overlap6": get-overlapping-interval(interval-from-datetime(datetime("1989-03-04T12:23:39"), datetime("2000-10-30T18:27:19")), interval-from-datetime(datetime("1844-03-03T11:19:39"), datetime("1888-10-10T23:18:00"))) }
				4255	</pre></div></div></li>
				4256
				4257	<li>
				4258	<p>The expected result is:</p>
				4259
				4260	<div class="source">
				4261	<div class="source">
				4262	<pre>{ "overlap1": interval-time("12:23:39.000Z, 18:27:19.000Z"),
				4263	"overlap2": null,
				4264	"overlap3": null,
				4265	"overlap4": interval-date("2013-01-01, 2014-01-01"),
				4266	"overlap5": interval-datetime("1989-03-04T12:23:39.000Z, 2000-10-30T18:27:19.000Z"),
				4267	"overlap6": null }
				4268	</pre></div></div></li>
				4269	</ul></div>
				4270	<div class="section">
				4271	<h3><a name="interval-beforeinterval-afterinterval-meetsinterval-met-byinterval-overlapsinterval-overlapped-byinterval-overlappinginterval-startsinterval-started-byinterval-coversinterval-covered-byinterval-endsinterval-ended-by"></a>interval-before/interval-after/interval-meets/interval-met-by/interval-overlaps/interval-overlapped-by/interval-overlapping/interval-starts/interval-started-by/interval-covers/interval-covered-by/interval-ends/interval-ended-by</h3>
				4272	<p>See the <a href="allens.html">Allen’s Relations</a>.</p></div>
				4273	<div class="section">
				4274	<h3><a name="interval-bin"></a>interval-bin</h3>
				4275
				4276	<ul>
				4277
				4278	<li>
				4279	<p>Syntax:</p>
				4280
				4281	<div class="source">
				4282	<div class="source">
				4283	<pre>interval-bin(time-to-bin, time-bin-anchor, duration-bin-size)
				4284	</pre></div></div></li>
				4285
				4286	<li>
				4287	<p>Return the <tt>interval</tt> value representing the bin containing the <tt>time-to-bin</tt> value.</p></li>
				4288
				4289	<li>Arguments:
				4290
				4291	<ul>
				4292
				4293	<li><tt>time-to-bin</tt>: a date/time/datetime value representing the time to be binned.</li>
				4294
				4295	<li><tt>time-bin-anchor</tt>: a date/time/datetime value representing an anchor of a bin starts. The type of this argument should be the same as the first <tt>time-to-bin</tt> argument.</li>
				4296
				4297	<li><tt>duration-bin-size</tt>: the duration value representing the size of the bin, in the type of year-month-duration or day-time-duration. The type of this duration should be compatible with the type of <tt>time-to-bin</tt>, so that the arithmetic operation between <tt>time-to-bin</tt> and <tt>duration-bin-size</tt> is well-defined. Currently AsterixDB supports the following arithmetic operations:
				4298
				4299	<ul>
				4300
				4301	<li>datetime +\|- year-month-duration</li>
				4302
				4303	<li>datetime +\|- day-time-duration</li>
				4304
				4305	<li>date +\|- year-month-duration</li>
				4306
				4307	<li>date +\|- day-time-duration</li>
				4308
				4309	<li>time +\|- day-time-duration</li>
				4310	</ul></li>
				4311	</ul></li>
				4312
				4313	<li>Return Value:
				4314
				4315	<ul>
				4316
				4317	<li>A <tt>interval</tt> value representing the bin containing the <tt>time-to-bin</tt> value. Note that the internal type of this interval value should be the same as the <tt>time-to-bin</tt> type.</li>
				4318	</ul></li>
				4319
				4320	<li>
				4321	<p>Example:</p>
				4322
				4323	<div class="source">
				4324	<div class="source">
				4325	<pre>let $c1 := date("2010-10-30")
				4326	let $c2 := datetime("-1987-11-19T23:49:23.938")
				4327	let $c3 := time("12:23:34.930+07:00")
				4328
				4329	return { "bin1": interval-bin($c1, date("1990-01-01"), year-month-duration("P1Y")),
				4330	"bin2": interval-bin($c2, datetime("1990-01-01T00:00:00.000Z"), year-month-duration("P6M")),
				4331	"bin3": interval-bin($c3, time("00:00:00"), day-time-duration("PD1M")),
				4332	"bin4": interval-bin($c2, datetime("2013-01-01T00:00:00.000"), day-time-duration("PT24H"))
				4333	</pre></div></div> }</li>
				4334
				4335	<li>
				4336	<p>The expected result is:</p>
				4337
				4338	<div class="source">
				4339	<div class="source">
				4340	<pre>{ "bin1": interval-date("2010-01-01, 2011-01-01"),
				4341	"bin2": interval-datetime("-1987-07-01T00:00:00.000Z, -1986-01-01T00:00:00.000Z"),
				4342	"bin3": interval-time("05:23:00.000Z, 05:24:00.000Z"),
				4343	"bin4": interval-datetime("-1987-11-19T00:00:00.000Z, -1987-11-20T00:00:00.000Z")}
				4344	</pre></div></div></li>
				4345	</ul></div>
				4346	<div class="section">
				4347	<h3><a name="interval-from-date"></a>interval-from-date</h3>
				4348
				4349	<ul>
				4350
				4351	<li>
				4352	<p>Syntax:</p>
				4353
				4354	<div class="source">
				4355	<div class="source">
				4356	<pre>interval-from-date(string_expression1, string_expression2)
				4357	</pre></div></div></li>
				4358
				4359	<li>
				4360	<p>Constructor function for the <tt>interval</tt> type by parsing two date strings.</p></li>
				4361
				4362	<li>Arguments:
				4363
				4364	<ul>
				4365
				4366	<li><tt>string_expression1</tt> : The <tt>string</tt> value representing the starting date.</li>
				4367
				4368	<li><tt>string_expression2</tt> : The <tt>string</tt> value representing the ending date.</li>
				4369	</ul></li>
				4370
				4371	<li>Return Value:
				4372
				4373	<ul>
				4374
				4375	<li>An <tt>interval</tt> value between the two dates.</li>
				4376	</ul></li>
				4377
				4378	<li>
				4379	<p>Example:</p>
				4380
				4381	<div class="source">
				4382	<div class="source">
				4383	<pre>{"date-interval": interval-from-date("2012-01-01", "2013-04-01")}
				4384	</pre></div></div></li>
				4385	</ul>
				4386
				4387	<ul>
				4388
				4389	<li>
				4390	<p>The expected result is:</p>
				4391
				4392	<div class="source">
				4393	<div class="source">
				4394	<pre>{ "date-interval": interval-date("2012-01-01, 2013-04-01") }
				4395	</pre></div></div></li>
				4396	</ul></div>
				4397	<div class="section">
				4398	<h3><a name="interval-from-time"></a>interval-from-time</h3>
				4399
				4400	<ul>
				4401
				4402	<li>
				4403	<p>Syntax:</p>
				4404
				4405	<div class="source">
				4406	<div class="source">
				4407	<pre>interval-from-time(string_expression1, string_expression2)
				4408	</pre></div></div></li>
				4409
				4410	<li>
				4411	<p>Constructor function for the <tt>interval</tt> type by parsing two time strings.</p></li>
				4412
				4413	<li>Arguments:
				4414
				4415	<ul>
				4416
				4417	<li><tt>string_expression1</tt> : The <tt>string</tt> value representing the starting time.</li>
				4418
				4419	<li><tt>string_expression2</tt> : The <tt>string</tt> value representing the ending time.</li>
				4420	</ul></li>
				4421
				4422	<li>Return Value:
				4423
				4424	<ul>
				4425
				4426	<li>An <tt>interval</tt> value between the two times.</li>
				4427	</ul></li>
				4428
				4429	<li>
				4430	<p>Example:</p>
				4431
				4432	<div class="source">
				4433	<div class="source">
				4434	<pre>{"time-interval": interval-from-time("12:23:34.456Z", "233445567+0800")}
				4435	</pre></div></div></li>
				4436	</ul>
				4437
				4438	<ul>
				4439
				4440	<li>
				4441	<p>The expected result is:</p>
				4442
				4443	<div class="source">
				4444	<div class="source">
				4445	<pre>{ "time-interval": interval-time("12:23:34.456Z, 15:34:45.567Z") }
				4446	</pre></div></div></li>
				4447	</ul></div>
				4448	<div class="section">
				4449	<h3><a name="interval-from-datetime"></a>interval-from-datetime</h3>
				4450
				4451	<ul>
				4452
				4453	<li>
				4454	<p>Syntax:</p>
				4455
				4456	<div class="source">
				4457	<div class="source">
				4458	<pre>interval-from-datetime(string_expression1, string_expression2)
				4459	</pre></div></div></li>
				4460
				4461	<li>
				4462	<p>Constructor function for <tt>interval</tt> type by parsing two datetime strings.</p></li>
				4463
				4464	<li>Arguments:
				4465
				4466	<ul>
				4467
				4468	<li><tt>string_expression1</tt> : The <tt>string</tt> value representing the starting datetime.</li>
				4469
				4470	<li><tt>string_expression2</tt> : The <tt>string</tt> value representing the ending datetime.</li>
				4471	</ul></li>
				4472
				4473	<li>Return Value:
				4474
				4475	<ul>
				4476
				4477	<li>An <tt>interval</tt> value between the two datetimes.</li>
				4478	</ul></li>
				4479
				4480	<li>
				4481	<p>Example:</p>
				4482
				4483	<div class="source">
				4484	<div class="source">
				4485	<pre>{"datetime-interval": interval-from-datetime("2012-01-01T12:23:34.456+08:00", "20130401T153445567Z")}
				4486	</pre></div></div></li>
				4487	</ul>
				4488
				4489	<ul>
				4490
				4491	<li>
				4492	<p>The expected result is:</p>
				4493
				4494	<div class="source">
				4495	<div class="source">
				4496	<pre>{ "datetime-interval": interval-datetime("2012-01-01T04:23:34.456Z, 2013-04-01T15:34:45.567Z") }
				4497	</pre></div></div></li>
				4498	</ul></div>
				4499	<div class="section">
				4500	<h3><a name="interval-start-from-datetimedatetime"></a>interval-start-from-date/time/datetime</h3>
				4501
				4502	<ul>
				4503
				4504	<li>
				4505	<p>Syntax:</p>
				4506
				4507	<div class="source">
				4508	<div class="source">
				4509	<pre>interval-start-from-date/time/datetime(date/time/datetime, duration)
				4510	</pre></div></div></li>
				4511
				4512	<li>
				4513	<p>Construct an <tt>interval</tt> value by the given starting <tt>date</tt>/<tt>time</tt>/<tt>datetime</tt> and the <tt>duration</tt> that the interval lasts.</p></li>
				4514
				4515	<li>Arguments:
				4516
				4517	<ul>
				4518
				4519	<li><tt>date/time/datetime</tt>: a <tt>string</tt> representing a <tt>date</tt>, <tt>time</tt> or <tt>datetime</tt>, or a <tt>date</tt>/<tt>time</tt>/<tt>datetime</tt> value, representing the starting time point.</li>
				4520
				4521	<li><tt>duration</tt>: a <tt>string</tt> or <tt>duration</tt> value representing the duration of the interval. Note that duration cannot be negative value.</li>
				4522	</ul></li>
				4523
				4524	<li>Return Value:
				4525
				4526	<ul>
				4527
				4528	<li>An <tt>interval</tt> value representing the interval starting from the given time point with the length of duration.</li>
				4529	</ul></li>
				4530
				4531	<li>
				4532	<p>Example:</p>
				4533
				4534	<div class="source">
				4535	<div class="source">
				4536	<pre>let $itv1 := interval-start-from-date("1984-01-01", "P1Y")
				4537	let $itv2 := interval-start-from-time(time("02:23:28.394"), "PT3H24M")
				4538	let $itv3 := interval-start-from-datetime("1999-09-09T09:09:09.999", duration("P2M30D"))
				4539	return {"interval1": $itv1, "interval2": $itv2, "interval3": $itv3}
				4540	</pre></div></div></li>
				4541
				4542	<li>
				4543	<p>The expectecd result is:</p>
				4544
				4545	<div class="source">
				4546	<div class="source">
				4547	<pre>{ "interval1": interval-date("1984-01-01, 1985-01-01"), "interval2": interval-time("02:23:28.394Z, 05:47:28.394Z"), "interval3": interval-datetime("1999-09-09T09:09:09.999Z, 1999-12-09T09:09:09.999Z") }
				4548	</pre></div></div></li>
				4549	</ul></div>
				4550	<div class="section">
				4551	<h3><a name="overlap-bins"></a>overlap-bins</h3>
				4552
				4553	<ul>
				4554
				4555	<li>
				4556	<p>Return Value:</p>
				4557
				4558	<ul>
				4559
				4560	<li>A <tt>interval</tt> value representing the bin containing the <tt>time-to-bin</tt> value. Note that the internal type of this interval value should be the same as the <tt>time-to-bin</tt> type.</li>
				4561	</ul></li>
				4562
				4563	<li>
				4564	<p>Syntax:</p>
				4565
				4566	<div class="source">
				4567	<div class="source">
				4568	<pre>overlap-bins(interval_expression, time-bin-anchor, duration-bin-size)
				4569	</pre></div></div></li>
				4570
				4571	<li>
				4572	<p>Returns an ordered list of <tt>interval</tt> values representing each bin that is overlapping the <tt>interval_expression</tt>.</p></li>
				4573
				4574	<li>Arguments:
				4575
				4576	<ul>
				4577
				4578	<li><tt>interval_expression</tt>: an <tt>interval</tt> value</li>
				4579
				4580	<li><tt>time-bin-anchor</tt>: a date/time/datetime value representing an anchor of a bin starts. The type of this argument should be the same as the first <tt>time-to-bin</tt> argument.</li>
				4581
				4582	<li><tt>duration-bin-size</tt>: the duration value representing the size of the bin, in the type of year-month-duration or day-time-duration. The type of this duration should be compatible with the type of <tt>time-to-bin</tt>, so that the arithmetic operation between <tt>time-to-bin</tt> and <tt>duration-bin-size</tt> is well-defined. Currently AsterixDB supports the following arithmetic operations:
				4583
				4584	<ul>
				4585
				4586	<li>datetime +\|- year-month-duration</li>
				4587
				4588	<li>datetime +\|- day-time-duration</li>
				4589
				4590	<li>date +\|- year-month-duration</li>
				4591
				4592	<li>date +\|- day-time-duration</li>
				4593
				4594	<li>time +\|- day-time-duration</li>
				4595	</ul></li>
				4596	</ul></li>
				4597
				4598	<li>Return Value:
				4599
				4600	<ul>
				4601
				4602	<li>A ordered list of <tt>interval</tt> values representing each bin that is overlapping the <tt>interval_expression</tt>. Note that the internal type as <tt>time-to-bin</tt> and <tt>duration-bin-size</tt>.</li>
				4603	</ul></li>
				4604
				4605	<li>
				4606	<p>Example:</p>
				4607
				4608	<div class="source">
				4609	<div class="source">
				4610	<pre>let $itv1 := interval-from-time(time("17:23:37"), time("18:30:21"))
				4611	let $itv2 := interval-from-date(date("1984-03-17"), date("2013-08-22"))
				4612	let $itv3 := interval-from-datetime(datetime("1800-01-01T23:59:48.938"), datetime("2015-07-26T13:28:30.218"))
				4613	return { "timebins": overlap-bins($itv1, time("00:00:00"), day-time-duration("PT30M")),
				4614	"datebins": overlap-bins($itv2, date("1990-01-01"), year-month-duration("P20Y")),
				4615	"datetimebins": overlap-bins($itv3, datetime("1900-01-01T00:00:00.000"), year-month-duration("P100Y")) }
				4616	</pre></div></div></li>
				4617
				4618	<li>
				4619	<p>The expected result is:</p>
				4620
				4621	<div class="source">
				4622	<div class="source">
				4623	<pre>{ "timebins": [ interval-time("17:00:00.000Z, 17:30:00.000Z"), interval-time("17:30:00.000Z, 18:00:00.000Z"), interval-time("18:00:00.000Z, 18:30:00.000Z"), interval-time("18:30:00.000Z, 19:00:00.000Z") ],
				4624	"datebins": [ interval-date("1970-01-01, 1990-01-01"), interval-date("1990-01-01, 2010-01-01"), interval-date("2010-01-01, 2030-01-01") ],
				4625	"datetimebins": [ interval-datetime("1800-01-01T00:00:00.000Z, 1900-01-01T00:00:00.000Z"), interval-datetime("1900-01-01T00:00:00.000Z, 2000-01-01T00:00:00.000Z"), interval-datetime("2000-01-01T00:00:00.000Z, 2100-01-01T00:00:00.000Z") ] }
				4626	</pre></div></div></li>
				4627	</ul></div></div>
				4628	<div class="section">
				4629	<h2><a name="Record_Functions_Back_to_TOC"></a><a name="RecordFunctions" id="RecordFunctions">Record Functions</a> <font size="4"><a href="#toc">[Back to TOC]</a></font></h2>
				4630	<div class="section">
				4631	<h3><a name="get-record-fields"></a>get-record-fields</h3>
				4632
				4633	<ul>
				4634
				4635	<li>
				4636	<p>Syntax:</p>
				4637
				4638	<div class="source">
				4639	<div class="source">
				4640	<pre>get-record-fields(record_expression)
				4641	</pre></div></div></li>
				4642
				4643	<li>
				4644	<p>Access the record field names, type and open status for a given record.</p></li>
				4645
				4646	<li>Arguments:
				4647
				4648	<ul>
				4649
				4650	<li><tt>record_expression</tt> : a record value.</li>
				4651	</ul></li>
				4652
				4653	<li>Return Value:
				4654
				4655	<ul>
				4656
				4657	<li>An order list of <tt>record</tt> values that include the field-name <tt>string</tt>, field-type <tt>string</tt>, is-open <tt>boolean</tt> and optional nested <tt>orderedList</tt> for the values of a nested record.</li>
				4658	</ul></li>
				4659
				4660	<li>
				4661	<p>Example:</p>
				4662
				4663	<div class="source">
				4664	<div class="source">
				4665	<pre>let $r1 := {"id": 1,
				4666	"project": "AsterixDB",
				4667	"address": {"city": "Irvine", "state": "CA"},
				4668	"related": ["Hivestrix", "Preglix", "Apache VXQuery"] }
				4669	return get-record-fields($r1)
				4670	</pre></div></div></li>
				4671
				4672	<li>
				4673	<p>The expected result is:</p>
				4674
				4675	<div class="source">
				4676	<div class="source">
				4677	<pre>[ { "field-name": "id", "field-type": "INT64", "is-open": false },
				4678	{ "field-name": "project", "field-type": "STRING", "is-open": false },
				4679	{ "field-name": "address", "field-type": "RECORD", "is-open": false, "nested": [
				4680	{ "field-name": "city", "field-type": "STRING", "is-open": false },
				4681	{ "field-name": "state", "field-type": "STRING", "is-open": false } ] },
				4682	{ "field-name": "related", "field-type": "ORDEREDLIST", "is-open": false, "list": [
				4683	{ "field-type": "STRING" },
				4684	{ "field-type": "STRING" },
				4685	{ "field-type": "STRING" } ] } ]
				4686	</pre></div></div></li>
				4687	</ul>
				4688	<p>]</p></div>
				4689	<div class="section">
				4690	<h3><a name="get-record-field-value"></a>get-record-field-value</h3>
				4691
				4692	<ul>
				4693
				4694	<li>
				4695	<p>Syntax:</p>
				4696
				4697	<div class="source">
				4698	<div class="source">
				4699	<pre>get-record-field-value(record_expression, string_expression)
				4700	</pre></div></div></li>
				4701
				4702	<li>
				4703	<p>Access the field name given in the <tt>string_expression</tt> from the <tt>record_expression</tt>.</p></li>
				4704
				4705	<li>Arguments:
				4706
				4707	<ul>
				4708
				4709	<li><tt>record_expression</tt> : A <tt>record</tt> value.</li>
				4710
				4711	<li><tt>string_expression</tt> : A <tt>string</tt> representing the top level field name.</li>
				4712	</ul></li>
				4713
				4714	<li>Return Value:
				4715
				4716	<ul>
				4717
				4718	<li>An <tt>any</tt> value saved in the designated field of the record.</li>
				4719	</ul></li>
				4720
				4721	<li>
				4722	<p>Example:</p>
				4723
				4724	<div class="source">
				4725	<div class="source">
				4726	<pre>let $r1 := {"id": 1,
				4727	"project": "AsterixDB",
				4728	"address": {"city": "Irvine", "state": "CA"},
				4729	"related": ["Hivestrix", "Preglix", "Apache VXQuery"] }
				4730	return get-record-field-value($r1, "project")
				4731	</pre></div></div></li>
				4732
				4733	<li>
				4734	<p>The expected result is:</p>
				4735
				4736	<div class="source">
				4737	<div class="source">
				4738	<pre>"AsterixDB"
				4739	</pre></div></div></li>
				4740	</ul></div></div>
				4741	<div class="section">
				4742	<h2><a name="Other_Functions_Back_to_TOC"></a><a name="OtherFunctions" id="OtherFunctions">Other Functions</a> <font size="4"><a href="#toc">[Back to TOC]</a></font></h2>
				4743	<div class="section">
				4744	<h3><a name="create-uuid"></a>create-uuid</h3>
				4745
				4746	<ul>
				4747
				4748	<li>
				4749	<p>Syntax:</p>
				4750
				4751	<div class="source">
				4752	<div class="source">
				4753	<pre>create-uuid()
				4754	</pre></div></div></li>
				4755
				4756	<li>
				4757	<p>Generates a <tt>uuid</tt>.</p></li>
				4758
				4759	<li>Arguments:
				4760
				4761	<ul>
				4762
				4763	<li>none</li>
				4764	</ul></li>
				4765
				4766	<li>Return Value:
				4767
				4768	<ul>
				4769
				4770	<li>A generated <tt>uuid</tt>.</li>
				4771	</ul></li>
				4772	</ul></div>
				4773	<div class="section">
				4774	<h3><a name="is-null"></a>is-null</h3>
				4775
				4776	<ul>
				4777
				4778	<li>
				4779	<p>Syntax:</p>
				4780
				4781	<div class="source">
				4782	<div class="source">
				4783	<pre>is-null(var)
				4784	</pre></div></div></li>
				4785
				4786	<li>
				4787	<p>Checks whether the given variable is a <tt>null</tt> value.</p></li>
				4788
				4789	<li>Arguments:
				4790
				4791	<ul>
				4792
				4793	<li><tt>var</tt> : A variable (any type is allowed).</li>
				4794	</ul></li>
				4795
				4796	<li>Return Value:
				4797
				4798	<ul>
				4799
				4800	<li>A <tt>boolean</tt> on whether the variable is a <tt>null</tt> or not.</li>
				4801	</ul></li>
				4802
				4803	<li>
				4804	<p>Example:</p>
				4805
				4806	<div class="source">
				4807	<div class="source">
				4808	<pre>for $m in ['hello', 'world', null]
				4809	where not(is-null($m))
				4810	return $m
				4811	</pre></div></div></li>
				4812	</ul>
				4813
				4814	<ul>
				4815
				4816	<li>
				4817	<p>The expected result is:</p>
				4818
				4819	<div class="source">
				4820	<div class="source">
				4821	<pre>"hello"
				4822	"world"
				4823	</pre></div></div></li>
				4824	</ul></div>
				4825	<div class="section">
				4826	<h3><a name="is-system-null"></a>is-system-null</h3>
				4827
				4828	<ul>
				4829
				4830	<li>
				4831	<p>Syntax:</p>
				4832
				4833	<div class="source">
				4834	<div class="source">
				4835	<pre>is-system-null(var)
				4836	</pre></div></div></li>
				4837
				4838	<li>
				4839	<p>Checks whether the given variable is a <tt>system null</tt> value.</p></li>
				4840
				4841	<li>Arguments:
				4842
				4843	<ul>
				4844
				4845	<li><tt>var</tt> : A variable (any type is allowed).</li>
				4846	</ul></li>
				4847
				4848	<li>Return Value:
				4849
				4850	<ul>
				4851
				4852	<li>A <tt>boolean</tt> on whether the variable is a <tt>system null</tt> or not.</li>
				4853	</ul></li>
				4854	</ul></div>
				4855	<div class="section">
				4856	<h3><a name="len"></a>len</h3>
				4857
				4858	<ul>
				4859
				4860	<li>
				4861	<p>Syntax:</p>
				4862	<p>len(list_expression)</p></li>
				4863
				4864	<li>
				4865	<p>Returns the length of the list list_expression.</p></li>
				4866
				4867	<li>Arguments:
				4868
				4869	<ul>
				4870
				4871	<li><tt>list_expression</tt> : An <tt>OrderedList</tt>, <tt>UnorderedList</tt> or <tt>null</tt>, represents the list need to be checked.</li>
				4872	</ul></li>
				4873
				4874	<li>Return Value:
				4875
				4876	<ul>
				4877
				4878	<li>An <tt>Int32</tt> that represents the length of list_expression.</li>
				4879	</ul></li>
				4880
				4881	<li>
				4882	<p>Example:</p>
				4883
				4884	<div class="source">
				4885	<div class="source">
				4886	<pre>use dataverse TinySocial;
				4887
				4888	let $l := ["ASTERIX", "Hyracks"]
				4889	return len($l)
				4890	</pre></div></div></li>
				4891	</ul>
				4892
				4893	<ul>
				4894
				4895	<li>
				4896	<p>The expected result is:</p>
				4897
				4898	<div class="source">
				4899	<div class="source">
				4900	<pre>2
				4901	</pre></div></div></li>
				4902	</ul></div>
				4903	<div class="section">
				4904	<h3><a name="not"></a>not</h3>
				4905
				4906	<ul>
				4907
				4908	<li>
				4909	<p>Syntax:</p>
				4910
				4911	<div class="source">
				4912	<div class="source">
				4913	<pre>not(var)
				4914	</pre></div></div></li>
				4915
				4916	<li>
				4917	<p>Inverts a <tt>boolean</tt> value</p></li>
				4918
				4919	<li>Arguments:
				4920
				4921	<ul>
				4922
				4923	<li><tt>var</tt> : A <tt>boolean</tt> (or <tt>null</tt>)</li>
				4924	</ul></li>
				4925
				4926	<li>Return Value:
				4927
				4928	<ul>
				4929
				4930	<li>A <tt>boolean</tt>, the inverse of <tt>var</tt>. returns <tt>null</tt> if <tt>var</tt> is null</li>
				4931	</ul></li>
				4932
				4933	<li>
				4934	<p>Example:</p>
				4935
				4936	<div class="source">
				4937	<div class="source">
				4938	<pre>for $m in ['hello', 'world', null]
				4939	where not(is-null($m))
				4940	return $m
				4941	</pre></div></div></li>
				4942
				4943	<li>
				4944	<p>The expected result is:</p>
				4945
				4946	<div class="source">
				4947	<div class="source">
				4948	<pre>"hello"
				4949	"world"
				4950	</pre></div></div></li>
				4951	</ul></div>
				4952	<div class="section">
				4953	<h3><a name="range"></a>range</h3>
				4954
				4955	<ul>
				4956
				4957	<li>
				4958	<p>Syntax:</p>
				4959
				4960	<div class="source">
				4961	<div class="source">
				4962	<pre>range(start_numeric_expression, end_numeric_expression)
				4963	</pre></div></div></li>
				4964
				4965	<li>
				4966	<p>Generates a series of <tt>int64</tt> values based start the <tt>start_numeric_expression</tt> until the <tt>end_numeric_expression</tt>. The <tt>range</tt> fucntion must be used list argument of a <tt>for</tt> expression.</p></li>
				4967
				4968	<li>Arguments:</li>
				4969
				4970	<li><tt>start_numeric_expression</tt>: A <tt>int8</tt>/<tt>int16</tt>/<tt>int32</tt>/<tt>int64</tt> value representing the start value.</li>
				4971
				4972	<li><tt>end_numeric_expression</tt>: A <tt>int8</tt>/<tt>int16</tt>/<tt>int32</tt>/<tt>int64</tt> value representing the max final value.</li>
				4973
				4974	<li>Return Value:
				4975
				4976	<ul>
				4977
				4978	<li>A generated <tt>uuid</tt>.</li>
				4979	</ul></li>
				4980
				4981	<li>
				4982	<p>Example:</p>
				4983
				4984	<div class="source">
				4985	<div class="source">
				4986	<pre>for $i in range(0, 3)
				4987	return $i;
				4988	</pre></div></div></li>
				4989
				4990	<li>
				4991	<p>The expected result is:</p>
				4992
				4993	<div class="source">
				4994	<div class="source">
				4995	<pre>[ 0
				4996	, 1
				4997	, 2
				4998	, 3
				4999	]
				5000	</pre></div></div></li>
				5001	</ul></div>
				5002	<div class="section">
				5003	<h3><a name="switch-case"></a>switch-case</h3>
				5004
				5005	<ul>
				5006
				5007	<li>
				5008	<p>Syntax:</p>
				5009
				5010	<div class="source">
				5011	<div class="source">
				5012	<pre>switch-case(condition,
				5013	case1, case1-result,
				5014	case2, case2-result,
				5015	...,
				5016	default, default-result
				5017	)
				5018	</pre></div></div></li>
				5019
				5020	<li>
				5021	<p>Switches amongst a sequence of cases and returns the result of the first matching case. If no match is found, the result of the default case is returned.</p></li>
				5022
				5023	<li>Arguments:
				5024
				5025	<ul>
				5026
				5027	<li><tt>condition</tt>: A variable (any type is allowed).</li>
				5028
				5029	<li><tt>caseI/default</tt>: A variable (any type is allowed).</li>
				5030
				5031	<li><tt>caseI/default-result</tt>: A variable (any type is allowed).</li>
				5032	</ul></li>
				5033
				5034	<li>Return Value:
				5035
				5036	<ul>
				5037
				5038	<li>Returns <tt>caseI-result</tt> if <tt>condition</tt> matches <tt>caseI</tt>, otherwise <tt>default-result</tt>.</li>
				5039	</ul></li>
				5040
				5041	<li>
				5042	<p>Example 1:</p>
				5043
				5044	<div class="source">
				5045	<div class="source">
				5046	<pre>switch-case("a",
				5047	"a", 0,
				5048	"x", 1,
				5049	"y", 2,
				5050	"z", 3
				5051	)
				5052	</pre></div></div></li>
				5053	</ul>
				5054
				5055	<ul>
				5056
				5057	<li>
				5058	<p>The expected result is:</p>
				5059
				5060	<div class="source">
				5061	<div class="source">
				5062	<pre>0
				5063	</pre></div></div></li>
				5064
				5065	<li>
				5066	<p>Example 2:</p>
				5067
				5068	<div class="source">
				5069	<div class="source">
				5070	<pre>switch-case("a",
				5071	"x", 1,
				5072	"y", 2,
				5073	"z", 3
				5074	)
				5075	</pre></div></div></li>
				5076
				5077	<li>
				5078	<p>The expected result is:</p>
				5079
				5080	<div class="source">
				5081	<div class="source">
				5082	<pre>3
				5083	</pre></div></div></li>
				5084	</ul></div></div>
				5085	</div>
				5086	</div>
				5087	</div>
				5088
				5089	<hr/>
				5090
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				5093	<div class="row span12">Copyright © 2015
				5094	<a href="http://www.apache.org/">The Apache Software Foundation</a>.
				5095	All Rights Reserved.
				5096
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