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				200	! --><h1>Asterix: Using Functions</h1>
				201	<div class="section">
				202	<h2><a name="Table_of_Contents"></a><a name="toc" id="toc">Table of Contents</a></h2>
				203
				204	<ul>
				205
				206	<li><a href="#NumericFunctions">Numeric Functions</a></li>
				207
				208	<li><a href="#StringFunctions">String Functions</a></li>
				209
				210	<li><a href="#AggregateFunctions">Aggregate Functions</a></li>
				211
				212	<li><a href="#SpatialFunctions">Spatial Functions</a></li>
				213
				214	<li><a href="#SimilarityFunctions">Similarity Functions</a></li>
				215
				216	<li><a href="#TokenizingFunctions">Tokenizing Functions</a></li>
				217
				218	<li><a href="#TemporalFunctions">Temporal Functions</a></li>
				219
				220	<li><a href="#RecordFunctions">Record Functions</a></li>
				221
				222	<li><a href="#OtherFunctions">Other Functions</a></li>
				223	</ul>
				224	<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>
				225	<div class="section">
				226	<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>
				227	<div class="section">
				228	<h3><a name="abs"></a>abs</h3>
				229
				230	<ul>
				231
				232	<li>
				233	<p>Syntax:</p>
				234
				235	<div class="source">
				236	<div class="source">
				237	<pre>abs(numeric_expression)
				238	</pre></div></div></li>
				239
				240	<li>
				241	<p>Computes the absolute value of the argument.</p></li>
				242
				243	<li>Arguments:
				244
				245	<ul>
				246
				247	<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>
				248	</ul></li>
				249
				250	<li>Return Value:
				251
				252	<ul>
				253
				254	<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>
				255	</ul></li>
				256
				257	<li>
				258	<p>Example:</p>
				259
				260	<div class="source">
				261	<div class="source">
				262	<pre>let $v1 := abs(2013)
				263	let $v2 := abs(-4036)
				264	let $v3 := abs(0)
				265	let $v4 := abs(float("-2013.5"))
				266	let $v5 := abs(double("-2013.593823748327284"))
				267	return { "v1": $v1, "v2": $v2, "v3": $v3, "v4": $v4, "v5": $v5 }
				268	</pre></div></div></li>
				269	</ul>
				270
				271	<ul>
				272
				273	<li>
				274	<p>The expected result is:</p>
				275
				276	<div class="source">
				277	<div class="source">
				278	<pre>{ "v1": 2013, "v2": 4036, "v3": 0, "v4": 2013.5f, "v5": 2013.5938237483274d }
				279	</pre></div></div></li>
				280	</ul></div>
				281	<div class="section">
				282	<h3><a name="ceiling"></a>ceiling</h3>
				283
				284	<ul>
				285
				286	<li>
				287	<p>Syntax:</p>
				288
				289	<div class="source">
				290	<div class="source">
				291	<pre>ceiling(numeric_expression)
				292	</pre></div></div></li>
				293
				294	<li>
				295	<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>
				296
				297	<li>Arguments:
				298
				299	<ul>
				300
				301	<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>
				302	</ul></li>
				303
				304	<li>Return Value:
				305
				306	<ul>
				307
				308	<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>
				309	</ul></li>
				310
				311	<li>
				312	<p>Example:</p>
				313
				314	<div class="source">
				315	<div class="source">
				316	<pre>let $v1 := ceiling(2013)
				317	let $v2 := ceiling(-4036)
				318	let $v3 := ceiling(0.3)
				319	let $v4 := ceiling(float("-2013.2"))
				320	let $v5 := ceiling(double("-2013.893823748327284"))
				321	return { "v1": $v1, "v2": $v2, "v3": $v3, "v4": $v4, "v5": $v5 }
				322	</pre></div></div></li>
				323	</ul>
				324
				325	<ul>
				326
				327	<li>
				328	<p>The expected result is:</p>
				329
				330	<div class="source">
				331	<div class="source">
				332	<pre>{ "v1": 2013, "v2": -4036, "v3": 1.0d, "v4": -2013.0f, "v5": -2013.0d }
				333	</pre></div></div></li>
				334	</ul></div>
				335	<div class="section">
				336	<h3><a name="floor"></a>floor</h3>
				337
				338	<ul>
				339
				340	<li>
				341	<p>Syntax:</p>
				342
				343	<div class="source">
				344	<div class="source">
				345	<pre>floor(numeric_expression)
				346	</pre></div></div></li>
				347
				348	<li>
				349	<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>
				350
				351	<li>Arguments:
				352
				353	<ul>
				354
				355	<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>
				356	</ul></li>
				357
				358	<li>Return Value:
				359
				360	<ul>
				361
				362	<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>
				363	</ul></li>
				364
				365	<li>
				366	<p>Example:</p>
				367
				368	<div class="source">
				369	<div class="source">
				370	<pre>let $v1 := floor(2013)
				371	let $v2 := floor(-4036)
				372	let $v3 := floor(0.8)
				373	let $v4 := floor(float("-2013.2"))
				374	let $v5 := floor(double("-2013.893823748327284"))
				375	return { "v1": $v1, "v2": $v2, "v3": $v3, "v4": $v4, "v5": $v5 }
				376	</pre></div></div></li>
				377	</ul>
				378
				379	<ul>
				380
				381	<li>
				382	<p>The expected result is:</p>
				383
				384	<div class="source">
				385	<div class="source">
				386	<pre>{ "v1": 2013, "v2": -4036, "v3": 0.0d, "v4": -2014.0f, "v5": -2014.0d }
				387	</pre></div></div></li>
				388	</ul></div>
				389	<div class="section">
				390	<h3><a name="round"></a>round</h3>
				391
				392	<ul>
				393
				394	<li>
				395	<p>Syntax:</p>
				396
				397	<div class="source">
				398	<div class="source">
				399	<pre>round(numeric_expression)
				400	</pre></div></div></li>
				401
				402	<li>
				403	<p>Computes the number with no fractional part that is closest (and also closest to positive infinity) to the argument.</p></li>
				404
				405	<li>Arguments:
				406
				407	<ul>
				408
				409	<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>
				410	</ul></li>
				411
				412	<li>Return Value:
				413
				414	<ul>
				415
				416	<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>
				417	</ul></li>
				418
				419	<li>
				420	<p>Example:</p>
				421
				422	<div class="source">
				423	<div class="source">
				424	<pre>let $v1 := round(2013)
				425	let $v2 := round(-4036)
				426	let $v3 := round(0.8)
				427	let $v4 := round(float("-2013.256"))
				428	let $v5 := round(double("-2013.893823748327284"))
				429	return { "v1": $v1, "v2": $v2, "v3": $v3, "v4": $v4, "v5": $v5 }
				430	</pre></div></div></li>
				431	</ul>
				432
				433	<ul>
				434
				435	<li>
				436	<p>The expected result is:</p>
				437
				438	<div class="source">
				439	<div class="source">
				440	<pre>{ "v1": 2013, "v2": -4036, "v3": 1.0d, "v4": -2013.0f, "v5": -2014.0d }
				441	</pre></div></div></li>
				442	</ul></div>
				443	<div class="section">
				444	<h3><a name="round-half-to-even"></a>round-half-to-even</h3>
				445
				446	<ul>
				447
				448	<li>
				449	<p>Syntax:</p>
				450
				451	<div class="source">
				452	<div class="source">
				453	<pre>round-half-to-even(numeric_expression, [precision])
				454	</pre></div></div></li>
				455
				456	<li>
				457	<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>
				458
				459	<li>Arguments:
				460
				461	<ul>
				462
				463	<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>
				464
				465	<li><tt>precision</tt>: An optional integer field representing the number of digits in the fraction of the the result</li>
				466	</ul></li>
				467
				468	<li>Return Value:
				469
				470	<ul>
				471
				472	<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>
				473	</ul></li>
				474
				475	<li>
				476	<p>Example:</p>
				477
				478	<div class="source">
				479	<div class="source">
				480	<pre>let $v1 := round-half-to-even(2013)
				481	let $v2 := round-half-to-even(-4036)
				482	let $v3 := round-half-to-even(0.8)
				483	let $v4 := round-half-to-even(float("-2013.256"))
				484	let $v5 := round-half-to-even(double("-2013.893823748327284"))
				485	let $v6 := round-half-to-even(double("-2013.893823748327284"), 2)
				486	let $v7 := round-half-to-even(2013, 4)
				487	let $v8 := round-half-to-even(float("-2013.256"), 5)
				488	return { "v1": $v1, "v2": $v2, "v3": $v3, "v4": $v4, "v5": $v5, "v6": $v6, "v7": $v7, "v8": $v8 }
				489	</pre></div></div></li>
				490	</ul>
				491
				492	<ul>
				493
				494	<li>
				495	<p>The expected result is:</p>
				496
				497	<div class="source">
				498	<div class="source">
				499	<pre>{ "v1": 2013, "v2": -4036, "v3": 1.0d, "v4": -2013.0f, "v5": -2014.0d, "v6": -2013.89d, "v7": 2013, "v8": -2013.256f }
				500	</pre></div></div></li>
				501	</ul></div></div>
				502	<div class="section">
				503	<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>
				504	<div class="section">
				505	<h3><a name="string-to-codepoint"></a>string-to-codepoint</h3>
				506
				507	<ul>
				508
				509	<li>
				510	<p>Syntax:</p>
				511
				512	<div class="source">
				513	<div class="source">
				514	<pre>string-to-codepoint(string_expression)
				515	</pre></div></div></li>
				516
				517	<li>
				518	<p>Converts the string <tt>string_expression</tt> to its code-based representation.</p></li>
				519
				520	<li>Arguments:
				521
				522	<ul>
				523
				524	<li><tt>string_expression</tt> : A <tt>string</tt> that will be converted.</li>
				525	</ul></li>
				526
				527	<li>Return Value:
				528
				529	<ul>
				530
				531	<li>An <tt>OrderedList</tt> of the code points for the string <tt>string_expression</tt>.</li>
				532	</ul></li>
				533	</ul></div>
				534	<div class="section">
				535	<h3><a name="codepoint-to-string"></a>codepoint-to-string</h3>
				536
				537	<ul>
				538
				539	<li>
				540	<p>Syntax:</p>
				541
				542	<div class="source">
				543	<div class="source">
				544	<pre>codepoint-to-string(list_expression)
				545	</pre></div></div></li>
				546
				547	<li>
				548	<p>Converts the ordered code-based representation <tt>list_expression</tt> to the corresponding string.</p></li>
				549
				550	<li>Arguments:
				551
				552	<ul>
				553
				554	<li><tt>list_expression</tt> : An <tt>OrderedList</tt> of code-points.</li>
				555	</ul></li>
				556
				557	<li>Return Value:
				558
				559	<ul>
				560
				561	<li>A <tt>string</tt> representation of <tt>list_expression</tt>.</li>
				562	</ul></li>
				563
				564	<li>
				565	<p>Example:</p>
				566
				567	<div class="source">
				568	<div class="source">
				569	<pre>use dataverse TinySocial;
				570
				571	let $s := "Hello ASTERIX!"
				572	let $l := string-to-codepoint($s)
				573	let $ss := codepoint-to-string($l)
				574	return {"codes": $l, "string": $ss}
				575	</pre></div></div></li>
				576	</ul>
				577
				578	<ul>
				579
				580	<li>
				581	<p>The expected result is:</p>
				582
				583	<div class="source">
				584	<div class="source">
				585	<pre>{ "codes": [ 72, 101, 108, 108, 111, 32, 65, 83, 84, 69, 82, 73, 88, 33 ], "string": "Hello ASTERIX!" }
				586	</pre></div></div></li>
				587	</ul></div>
				588	<div class="section">
				589	<h3><a name="contains"></a>contains</h3>
				590
				591	<ul>
				592
				593	<li>
				594	<p>Syntax:</p>
				595
				596	<div class="source">
				597	<div class="source">
				598	<pre>contains(string_expression, substring_to_contain)
				599	</pre></div></div></li>
				600
				601	<li>
				602	<p>Checks whether the string <tt>string_expression</tt> contains the string <tt>substring_to_contain</tt></p></li>
				603
				604	<li>Arguments:
				605
				606	<ul>
				607
				608	<li><tt>string_expression</tt> : A <tt>string</tt> that might contain the given substring.</li>
				609
				610	<li><tt>substring_to_contain</tt> : A target <tt>string</tt> that might be contained.</li>
				611	</ul></li>
				612
				613	<li>Return Value:
				614
				615	<ul>
				616
				617	<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>
				618	</ul></li>
				619
				620	<li>Note: An <a href="similarity.html#UsingIndexesToSupportSimilarityQueries">n-gram index</a> can be utilized for this function.</li>
				621
				622	<li>
				623	<p>Example:</p>
				624
				625	<div class="source">
				626	<div class="source">
				627	<pre>use dataverse TinySocial;
				628
				629	for $i in dataset('FacebookMessages')
				630	where contains($i.message, "phone")
				631	return {"mid": $i.message-id, "message": $i.message}
				632	</pre></div></div></li>
				633	</ul>
				634
				635	<ul>
				636
				637	<li>
				638	<p>The expected result is:</p>
				639
				640	<div class="source">
				641	<div class="source">
				642	<pre>{ "mid": 2, "message": " dislike iphone its touch-screen is horrible" }
				643	{ "mid": 13, "message": " dislike iphone the voice-command is bad:(" }
				644	{ "mid": 15, "message": " like iphone the voicemail-service is awesome" }
				645	</pre></div></div></li>
				646	</ul></div>
				647	<div class="section">
				648	<h3><a name="like"></a>like</h3>
				649
				650	<ul>
				651
				652	<li>
				653	<p>Syntax:</p>
				654
				655	<div class="source">
				656	<div class="source">
				657	<pre>like(string_expression, string_pattern)
				658	</pre></div></div></li>
				659
				660	<li>
				661	<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>
				662
				663	<li>Arguments:
				664
				665	<ul>
				666
				667	<li><tt>string_expression</tt> : A <tt>string</tt> that might contain the pattern or <tt>null</tt>.</li>
				668
				669	<li><tt>string_pattern</tt> : A pattern <tt>string</tt> that might be contained or <tt>null</tt>.</li>
				670	</ul></li>
				671
				672	<li>Return Value:
				673
				674	<ul>
				675
				676	<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>
				677	</ul></li>
				678
				679	<li>
				680	<p>Example:</p>
				681
				682	<div class="source">
				683	<div class="source">
				684	<pre>use dataverse TinySocial;
				685
				686	for $i in dataset('FacebookMessages')
				687	where like($i.message, "%at&t%")
				688	return $i.message
				689	</pre></div></div></li>
				690	</ul>
				691
				692	<ul>
				693
				694	<li>
				695	<p>The expected result is:</p>
				696
				697	<div class="source">
				698	<div class="source">
				699	<pre>" can't stand at&t the network is horrible:("
				700	" can't stand at&t its plan is terrible"
				701	" love at&t its 3G is good:)"
				702	</pre></div></div></li>
				703	</ul></div>
				704	<div class="section">
				705	<h3><a name="starts-with"></a>starts-with</h3>
				706
				707	<ul>
				708
				709	<li>
				710	<p>Syntax:</p>
				711
				712	<div class="source">
				713	<div class="source">
				714	<pre>starts-with(string_expression, substring_to_start_with)
				715	</pre></div></div></li>
				716
				717	<li>
				718	<p>Checks whether the string <tt>string_expression</tt> starts with the string <tt>substring_to_start_with</tt>.</p></li>
				719
				720	<li>Arguments:
				721
				722	<ul>
				723
				724	<li><tt>string_expression</tt> : A <tt>string</tt> that might start with the given string.</li>
				725
				726	<li><tt>substring_to_start_with</tt> : A <tt>string</tt> that might be contained as the starting substring.</li>
				727	</ul></li>
				728
				729	<li>Return Value:
				730
				731	<ul>
				732
				733	<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>
				734	</ul></li>
				735
				736	<li>
				737	<p>Example:</p>
				738
				739	<div class="source">
				740	<div class="source">
				741	<pre>use dataverse TinySocial;
				742
				743	for $i in dataset('FacebookMessages')
				744	where starts-with($i.message, " like")
				745	return $i.message
				746	</pre></div></div></li>
				747	</ul>
				748
				749	<ul>
				750
				751	<li>
				752	<p>The expected result is:</p>
				753
				754	<div class="source">
				755	<div class="source">
				756	<pre>" like samsung the plan is amazing"
				757	" like t-mobile its platform is mind-blowing"
				758	" like verizon the 3G is awesome:)"
				759	" like iphone the voicemail-service is awesome"
				760	</pre></div></div></li>
				761	</ul></div>
				762	<div class="section">
				763	<h3><a name="ends-with"></a>ends-with</h3>
				764
				765	<ul>
				766
				767	<li>
				768	<p>Syntax:</p>
				769
				770	<div class="source">
				771	<div class="source">
				772	<pre>ends-with(string_expression, substring_to_end_with)
				773	</pre></div></div></li>
				774
				775	<li>
				776	<p>Checks whether the string <tt>string_expression</tt> ends with the string <tt>substring_to_end_with</tt>.</p></li>
				777
				778	<li>Arguments:
				779
				780	<ul>
				781
				782	<li><tt>string_expression</tt> : A <tt>string</tt> that might end with the given string.</li>
				783
				784	<li><tt>substring_to_end_with</tt> : A <tt>string</tt> that might be contained as the ending substring.</li>
				785	</ul></li>
				786
				787	<li>Return Value:
				788
				789	<ul>
				790
				791	<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>
				792	</ul></li>
				793
				794	<li>
				795	<p>Example:</p>
				796
				797	<div class="source">
				798	<div class="source">
				799	<pre>use dataverse TinySocial;
				800
				801	for $i in dataset('FacebookMessages')
				802	where ends-with($i.message, ":)")
				803	return $i.message
				804	</pre></div></div></li>
				805	</ul>
				806
				807	<ul>
				808
				809	<li>
				810	<p>The expected result is:</p>
				811
				812	<div class="source">
				813	<div class="source">
				814	<pre>" love sprint its shortcut-menu is awesome:)"
				815	" like verizon the 3G is awesome:)"
				816	" love at&t its 3G is good:)"
				817	</pre></div></div></li>
				818	</ul></div>
				819	<div class="section">
				820	<h3><a name="string-concat"></a>string-concat</h3>
				821
				822	<ul>
				823
				824	<li>
				825	<p>Syntax:</p>
				826
				827	<div class="source">
				828	<div class="source">
				829	<pre>string-concat(list_expression)
				830	</pre></div></div></li>
				831
				832	<li>
				833	<p>Concatenates a list of strings <tt>list_expression</tt> into a single string.</p></li>
				834
				835	<li>Arguments:
				836
				837	<ul>
				838
				839	<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>
				840	</ul></li>
				841
				842	<li>Return Value:
				843
				844	<ul>
				845
				846	<li>Returns the concatenated <tt>string</tt> value.</li>
				847	</ul></li>
				848
				849	<li>
				850	<p>Example:</p>
				851
				852	<div class="source">
				853	<div class="source">
				854	<pre>let $i := "ASTERIX"
				855	let $j := " "
				856	let $k := "ROCKS!"
				857	return string-concat([$i, $j, $k])
				858	</pre></div></div></li>
				859	</ul>
				860
				861	<ul>
				862
				863	<li>
				864	<p>The expected result is:</p>
				865
				866	<div class="source">
				867	<div class="source">
				868	<pre>"ASTERIX ROCKS!"
				869	</pre></div></div></li>
				870	</ul></div>
				871	<div class="section">
				872	<h3><a name="string-join"></a>string-join</h3>
				873
				874	<ul>
				875
				876	<li>
				877	<p>Syntax:</p>
				878
				879	<div class="source">
				880	<div class="source">
				881	<pre>string-join(list_expression, string_expression)
				882	</pre></div></div></li>
				883
				884	<li>
				885	<p>Joins a list of strings <tt>list_expression</tt> with the given separator <tt>string_expression</tt> into a single string.</p></li>
				886
				887	<li>Arguments:
				888
				889	<ul>
				890
				891	<li><tt>list_expression</tt> : An <tt>OrderedList</tt> or <tt>UnorderedList</tt> of strings (could be <tt>null</tt>) to be joined.</li>
				892
				893	<li><tt>string_expression</tt> : A <tt>string</tt> as the separator.</li>
				894	</ul></li>
				895
				896	<li>Return Value:
				897
				898	<ul>
				899
				900	<li>Returns the joined <tt>String</tt>.</li>
				901	</ul></li>
				902
				903	<li>
				904	<p>Example:</p>
				905
				906	<div class="source">
				907	<div class="source">
				908	<pre>use dataverse TinySocial;
				909
				910	let $i := ["ASTERIX", "ROCKS~"]
				911	return string-join($i, "!! ")
				912	</pre></div></div></li>
				913	</ul>
				914
				915	<ul>
				916
				917	<li>
				918	<p>The expected result is:</p>
				919
				920	<div class="source">
				921	<div class="source">
				922	<pre>"ASTERIX!! ROCKS~"
				923	</pre></div></div></li>
				924	</ul></div>
				925	<div class="section">
				926	<h3><a name="lowercase"></a>lowercase</h3>
				927
				928	<ul>
				929
				930	<li>
				931	<p>Syntax:</p>
				932
				933	<div class="source">
				934	<div class="source">
				935	<pre>lowercase(string_expression)
				936	</pre></div></div></li>
				937
				938	<li>
				939	<p>Converts a given string <tt>string_expression</tt> to its lowercase form.</p></li>
				940
				941	<li>Arguments:
				942
				943	<ul>
				944
				945	<li><tt>string_expression</tt> : A <tt>string</tt> to be converted.</li>
				946	</ul></li>
				947
				948	<li>Return Value:
				949
				950	<ul>
				951
				952	<li>Returns a <tt>string</tt> as the lowercase form of the given <tt>string_expression</tt>.</li>
				953	</ul></li>
				954
				955	<li>
				956	<p>Example:</p>
				957
				958	<div class="source">
				959	<div class="source">
				960	<pre>use dataverse TinySocial;
				961
				962	let $i := "ASTERIX"
				963	return lowercase($i)
				964	</pre></div></div></li>
				965	</ul>
				966
				967	<ul>
				968
				969	<li>
				970	<p>The expected result is:</p>
				971
				972	<div class="source">
				973	<div class="source">
				974	<pre>asterix
				975	</pre></div></div></li>
				976	</ul></div>
				977	<div class="section">
				978	<h3><a name="uppercase"></a>uppercase</h3>
				979
				980	<ul>
				981
				982	<li>Syntax:</li>
				983	</ul>
				984	<p>uppercase(string_expression)</p>
				985
				986	<ul>
				987
				988	<li>Converts a given string <tt>string_expression</tt> to its uppercase form.</li>
				989
				990	<li>Arguments:
				991
				992	<ul>
				993
				994	<li><tt>string_expression</tt> : A <tt>string</tt> to be converted.</li>
				995	</ul></li>
				996
				997	<li>Return Value:
				998
				999	<ul>
				1000
				1001	<li>Returns a <tt>string</tt> as the uppercase form of the given <tt>string_expression</tt>.</li>
				1002	</ul></li>
				1003
				1004	<li>
				1005	<p>Example:</p>
				1006
				1007	<div class="source">
				1008	<div class="source">
				1009	<pre>use dataverse TinySocial;
				1010
				1011	let $i := "asterix"
				1012	return uppercase($i)
				1013	</pre></div></div></li>
				1014	</ul>
				1015
				1016	<ul>
				1017
				1018	<li>
				1019	<p>The expected result is:</p>
				1020
				1021	<div class="source">
				1022	<div class="source">
				1023	<pre>ASTERIX
				1024	</pre></div></div></li>
				1025	</ul></div>
				1026	<div class="section">
				1027	<h3><a name="uppercase"></a>uppercase</h3>
				1028
				1029	<ul>
				1030
				1031	<li>
				1032	<p>Syntax:</p>
				1033
				1034	<div class="source">
				1035	<div class="source">
				1036	<pre>uppercase(string_expression)
				1037	</pre></div></div></li>
				1038
				1039	<li>
				1040	<p>Converts a given string <tt>string_expression</tt> to its uppercase form.</p></li>
				1041
				1042	<li>Arguments:
				1043
				1044	<ul>
				1045
				1046	<li><tt>string_expression</tt> : A <tt>string</tt> to be converted.</li>
				1047	</ul></li>
				1048
				1049	<li>Return Value:
				1050
				1051	<ul>
				1052
				1053	<li>Returns a <tt>string</tt> as the uppercase form of the given <tt>string_expression</tt>.</li>
				1054	</ul></li>
				1055
				1056	<li>
				1057	<p>Example:</p>
				1058
				1059	<div class="source">
				1060	<div class="source">
				1061	<pre>use dataverse TinySocial;
				1062
				1063	let $i := "asterix"
				1064	return uppercase($i)
				1065	</pre></div></div></li>
				1066	</ul>
				1067
				1068	<ul>
				1069
				1070	<li>
				1071	<p>The expected result is:</p>
				1072
				1073	<div class="source">
				1074	<div class="source">
				1075	<pre>ASTERIX
				1076	</pre></div></div></li>
				1077	</ul></div>
				1078	<div class="section">
				1079	<h3><a name="matches"></a>matches</h3>
				1080
				1081	<ul>
				1082
				1083	<li>
				1084	<p>Syntax:</p>
				1085
				1086	<div class="source">
				1087	<div class="source">
				1088	<pre>matches(string_expression, string_pattern)
				1089	</pre></div></div></li>
				1090
				1091	<li>
				1092	<p>Checks whether the strings <tt>string_expression</tt> matches the given pattern <tt>string_pattern</tt> (A Java regular expression pattern).</p></li>
				1093
				1094	<li>Arguments:
				1095
				1096	<ul>
				1097
				1098	<li><tt>string_expression</tt> : A <tt>string</tt> that might contain the pattern.</li>
				1099
				1100	<li><tt>string_pattern</tt> : A pattern <tt>string</tt> to be matched.</li>
				1101	</ul></li>
				1102
				1103	<li>Return Value:
				1104
				1105	<ul>
				1106
				1107	<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>
				1108	</ul></li>
				1109
				1110	<li>
				1111	<p>Example:</p>
				1112
				1113	<div class="source">
				1114	<div class="source">
				1115	<pre>use dataverse TinySocial;
				1116
				1117	for $i in dataset('FacebookMessages')
				1118	where matches($i.message, "dislike iphone")
				1119	return $i.message
				1120	</pre></div></div></li>
				1121	</ul>
				1122
				1123	<ul>
				1124
				1125	<li>
				1126	<p>The expected result is:</p>
				1127
				1128	<div class="source">
				1129	<div class="source">
				1130	<pre>" dislike iphone its touch-screen is horrible"
				1131	" dislike iphone the voice-command is bad:("
				1132	</pre></div></div></li>
				1133	</ul></div>
				1134	<div class="section">
				1135	<h3><a name="replace"></a>replace</h3>
				1136
				1137	<ul>
				1138
				1139	<li>
				1140	<p>Syntax:</p>
				1141
				1142	<div class="source">
				1143	<div class="source">
				1144	<pre>replace(string_expression, string_pattern, string_replacement[, string_flags])
				1145	</pre></div></div></li>
				1146
				1147	<li>
				1148	<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>
				1149
				1150	<li>Arguments:
				1151
				1152	<ul>
				1153
				1154	<li><tt>string_expression</tt> : A <tt>string</tt> that might contain the pattern.</li>
				1155
				1156	<li><tt>string_pattern</tt> : A pattern <tt>string</tt> to be matched.</li>
				1157
				1158	<li><tt>string_replacement</tt> : A pattern <tt>string</tt> to be used as the replacement.</li>
				1159
				1160	<li><tt>string_flag</tt> : (Optional) A <tt>string</tt> with flags to be used during replace.</li>
				1161
				1162	<li>The following modes are enabled with these flags: dotall (s), multiline (m), case-insenitive (i), and comments and whitespace (x).</li>
				1163	</ul></li>
				1164
				1165	<li>Return Value:
				1166
				1167	<ul>
				1168
				1169	<li>Returns a <tt>string</tt> that is obtained after the replacements.</li>
				1170	</ul></li>
				1171
				1172	<li>
				1173	<p>Example:</p>
				1174
				1175	<div class="source">
				1176	<div class="source">
				1177	<pre>use dataverse TinySocial;
				1178
				1179	for $i in dataset('FacebookMessages')
				1180	where matches($i.message, " like iphone")
				1181	return replace($i.message, " like iphone", "like android")
				1182	</pre></div></div></li>
				1183	</ul>
				1184
				1185	<ul>
				1186
				1187	<li>
				1188	<p>The expected result is:</p>
				1189
				1190	<div class="source">
				1191	<div class="source">
				1192	<pre>"like android the voicemail-service is awesome"
				1193	</pre></div></div></li>
				1194	</ul></div>
				1195	<div class="section">
				1196	<h3><a name="string-length"></a>string-length</h3>
				1197
				1198	<ul>
				1199
				1200	<li>
				1201	<p>Syntax:</p>
				1202
				1203	<div class="source">
				1204	<div class="source">
				1205	<pre>string-length(string_expression)
				1206	</pre></div></div></li>
				1207
				1208	<li>
				1209	<p>Returns the length of the string <tt>string_expression</tt>.</p></li>
				1210
				1211	<li>Arguments:
				1212
				1213	<ul>
				1214
				1215	<li><tt>string_expression</tt> : A <tt>string</tt> or <tt>null</tt> that represents the string to be checked.</li>
				1216	</ul></li>
				1217
				1218	<li>Return Value:
				1219
				1220	<ul>
				1221
				1222	<li>An <tt>int64</tt> that represents the length of <tt>string_expression</tt>.</li>
				1223	</ul></li>
				1224
				1225	<li>
				1226	<p>Example:</p>
				1227
				1228	<div class="source">
				1229	<div class="source">
				1230	<pre>use dataverse TinySocial;
				1231
				1232	for $i in dataset('FacebookMessages')
				1233	return {"mid": $i.message-id, "message-len": string-length($i.message)}
				1234	</pre></div></div></li>
				1235	</ul>
				1236
				1237	<ul>
				1238
				1239	<li>
				1240	<p>The expected result is:</p>
				1241
				1242	<div class="source">
				1243	<div class="source">
				1244	<pre>{ "mid": 1, "message-len": 43 }
				1245	{ "mid": 2, "message-len": 44 }
				1246	{ "mid": 3, "message-len": 33 }
				1247	{ "mid": 4, "message-len": 43 }
				1248	{ "mid": 5, "message-len": 46 }
				1249	{ "mid": 6, "message-len": 43 }
				1250	{ "mid": 7, "message-len": 37 }
				1251	{ "mid": 8, "message-len": 33 }
				1252	{ "mid": 9, "message-len": 34 }
				1253	{ "mid": 10, "message-len": 50 }
				1254	{ "mid": 11, "message-len": 38 }
				1255	{ "mid": 12, "message-len": 52 }
				1256	{ "mid": 13, "message-len": 42 }
				1257	{ "mid": 14, "message-len": 27 }
				1258	{ "mid": 15, "message-len": 45 }
				1259	</pre></div></div></li>
				1260	</ul></div>
				1261	<div class="section">
				1262	<h3><a name="substring"></a>substring</h3>
				1263
				1264	<ul>
				1265
				1266	<li>
				1267	<p>Syntax:</p>
				1268
				1269	<div class="source">
				1270	<div class="source">
				1271	<pre>substring(string_expression, offset[, length])
				1272	</pre></div></div></li>
				1273
				1274	<li>
				1275	<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>
				1276
				1277	<li>Arguments:
				1278
				1279	<ul>
				1280
				1281	<li><tt>string_expression</tt> : A <tt>string</tt> to be extracted.</li>
				1282
				1283	<li><tt>offset</tt> : An <tt>int64</tt> as the starting offset of the substring in <tt>string_expression</tt>.</li>
				1284
				1285	<li><tt>length</tt> : (Optional) An <tt>int64</tt> as the length of the substring.</li>
				1286	</ul></li>
				1287
				1288	<li>Return Value:
				1289
				1290	<ul>
				1291
				1292	<li>A <tt>string</tt> that represents the substring.</li>
				1293	</ul></li>
				1294
				1295	<li>
				1296	<p>Example:</p>
				1297
				1298	<div class="source">
				1299	<div class="source">
				1300	<pre>use dataverse TinySocial;
				1301
				1302	for $i in dataset('FacebookMessages')
				1303	where string-length($i.message) > 50
				1304	return substring($i.message, 50)
				1305	</pre></div></div></li>
				1306	</ul>
				1307
				1308	<ul>
				1309
				1310	<li>
				1311	<p>The expected result is:</p>
				1312
				1313	<div class="source">
				1314	<div class="source">
				1315	<pre>"G:("
				1316	</pre></div></div></li>
				1317	</ul></div>
				1318	<div class="section">
				1319	<h3><a name="substring-before"></a>substring-before</h3>
				1320
				1321	<ul>
				1322
				1323	<li>
				1324	<p>Syntax:</p>
				1325
				1326	<div class="source">
				1327	<div class="source">
				1328	<pre>substring-before(string_expression, string_pattern)
				1329	</pre></div></div></li>
				1330
				1331	<li>
				1332	<p>Returns the substring from the given string <tt>string_expression</tt> before the given pattern <tt>string_pattern</tt>.</p></li>
				1333
				1334	<li>Arguments:
				1335
				1336	<ul>
				1337
				1338	<li><tt>string_expression</tt> : A <tt>string</tt> to be extracted.</li>
				1339
				1340	<li><tt>string_pattern</tt> : A <tt>string</tt> pattern to be searched.</li>
				1341	</ul></li>
				1342
				1343	<li>Return Value:
				1344
				1345	<ul>
				1346
				1347	<li>A <tt>string</tt> that represents the substring.</li>
				1348	</ul></li>
				1349
				1350	<li>
				1351	<p>Example:</p>
				1352
				1353	<div class="source">
				1354	<div class="source">
				1355	<pre>use dataverse TinySocial;
				1356
				1357	for $i in dataset('FacebookMessages')
				1358	where contains($i.message, "iphone")
				1359	return substring-before($i.message, "iphone")
				1360	</pre></div></div></li>
				1361	</ul>
				1362
				1363	<ul>
				1364
				1365	<li>
				1366	<p>The expected result is:</p>
				1367
				1368	<div class="source">
				1369	<div class="source">
				1370	<pre>" dislike "
				1371	" dislike "
				1372	" like "
				1373	</pre></div></div></li>
				1374	</ul></div>
				1375	<div class="section">
				1376	<h3><a name="substring-after"></a>substring-after</h3>
				1377
				1378	<ul>
				1379
				1380	<li>
				1381	<p>Syntax:</p>
				1382
				1383	<div class="source">
				1384	<div class="source">
				1385	<pre>substring-after(string_expression, string_pattern)
				1386	</pre></div></div></li>
				1387
				1388	<li>
				1389	<p>Returns the substring from the given string <tt>string_expression</tt> after the given pattern <tt>string_pattern</tt>.</p></li>
				1390
				1391	<li>Arguments:
				1392
				1393	<ul>
				1394
				1395	<li><tt>string_expression</tt> : A <tt>string</tt> to be extracted.</li>
				1396
				1397	<li><tt>string_pattern</tt> : A <tt>string</tt> pattern to be searched.</li>
				1398	</ul></li>
				1399
				1400	<li>Return Value:
				1401
				1402	<ul>
				1403
				1404	<li>A <tt>string</tt> that represents the substring.</li>
				1405	</ul></li>
				1406
				1407	<li>
				1408	<p>Example:</p>
				1409
				1410	<div class="source">
				1411	<div class="source">
				1412	<pre>use dataverse TinySocial;
				1413
				1414	for $i in dataset('FacebookMessages')
				1415	where contains($i.message, "iphone")
				1416	return substring-after($i.message, "iphone")
				1417	</pre></div></div></li>
				1418	</ul>
				1419
				1420	<ul>
				1421
				1422	<li>
				1423	<p>The expected result is:</p>
				1424
				1425	<div class="source">
				1426	<div class="source">
				1427	<pre>" its touch-screen is horrible"
				1428	" the voice-command is bad:("
				1429	" the voicemail-service is awesome"
				1430	</pre></div></div></li>
				1431	</ul></div></div>
				1432	<div class="section">
				1433	<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>
				1434	<div class="section">
				1435	<h3><a name="count"></a>count</h3>
				1436
				1437	<ul>
				1438
				1439	<li>
				1440	<p>Syntax:</p>
				1441
				1442	<div class="source">
				1443	<div class="source">
				1444	<pre>count(list)
				1445	</pre></div></div></li>
				1446
				1447	<li>
				1448	<p>Gets the number of items in the given list.</p></li>
				1449
				1450	<li>Arguments:
				1451
				1452	<ul>
				1453
				1454	<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>
				1455	</ul></li>
				1456
				1457	<li>Return Value:
				1458
				1459	<ul>
				1460
				1461	<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>
				1462	</ul></li>
				1463
				1464	<li>
				1465	<p>Example:</p>
				1466
				1467	<div class="source">
				1468	<div class="source">
				1469	<pre>use dataverse TinySocial;
				1470
				1471	let $l1 := ['hello', 'world', 1, 2, 3]
				1472	let $l2 := for $i in dataset TwitterUsers return $i
				1473	return {"count1": count($l1), "count2": count($l2)}
				1474	</pre></div></div></li>
				1475
				1476	<li>
				1477	<p>The expected result is:</p>
				1478
				1479	<div class="source">
				1480	<div class="source">
				1481	<pre>{ "count1": 5i64, "count2": 4i64 }
				1482	</pre></div></div></li>
				1483	</ul></div>
				1484	<div class="section">
				1485	<h3><a name="avg"></a>avg</h3>
				1486
				1487	<ul>
				1488
				1489	<li>
				1490	<p>Syntax:</p>
				1491
				1492	<div class="source">
				1493	<div class="source">
				1494	<pre>avg(num_list)
				1495	</pre></div></div></li>
				1496
				1497	<li>
				1498	<p>Gets the average value of the items in the given list.</p></li>
				1499
				1500	<li>Arguments:
				1501
				1502	<ul>
				1503
				1504	<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>
				1505	</ul></li>
				1506
				1507	<li>Return Value:
				1508
				1509	<ul>
				1510
				1511	<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>
				1512	</ul></li>
				1513
				1514	<li>
				1515	<p>Example:</p>
				1516
				1517	<div class="source">
				1518	<div class="source">
				1519	<pre>use dataverse TinySocial;
				1520
				1521	let $l := for $i in dataset TwitterUsers return $i.friends_count
				1522	return {"avg_friend_count": avg($l)}
				1523	</pre></div></div></li>
				1524
				1525	<li>
				1526	<p>The expected result is:</p>
				1527
				1528	<div class="source">
				1529	<div class="source">
				1530	<pre>{ "avg_friend_count": 191.5d }
				1531	</pre></div></div></li>
				1532	</ul></div>
				1533	<div class="section">
				1534	<h3><a name="sum"></a>sum</h3>
				1535
				1536	<ul>
				1537
				1538	<li>
				1539	<p>Syntax:</p>
				1540
				1541	<div class="source">
				1542	<div class="source">
				1543	<pre>sum(num_list)
				1544	</pre></div></div></li>
				1545
				1546	<li>
				1547	<p>Gets the sum of the items in the given list.</p></li>
				1548
				1549	<li>Arguments:
				1550
				1551	<ul>
				1552
				1553	<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>
				1554	</ul></li>
				1555
				1556	<li>Return Value:
				1557
				1558	<ul>
				1559
				1560	<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>
				1561	</ul></li>
				1562
				1563	<li>
				1564	<p>Example:</p>
				1565
				1566	<div class="source">
				1567	<div class="source">
				1568	<pre>use dataverse TinySocial;
				1569
				1570	let $l := for $i in dataset TwitterUsers return $i.friends_count
				1571	return {"sum_friend_count": sum($l)}
				1572	</pre></div></div></li>
				1573
				1574	<li>
				1575	<p>The expected result is:</p>
				1576
				1577	<div class="source">
				1578	<div class="source">
				1579	<pre>{ "sum_friend_count": 766 }
				1580	</pre></div></div></li>
				1581	</ul></div>
				1582	<div class="section">
				1583	<h3><a name="minmax"></a>min/max</h3>
				1584
				1585	<ul>
				1586
				1587	<li>
				1588	<p>Syntax:</p>
				1589
				1590	<div class="source">
				1591	<div class="source">
				1592	<pre>min(num_list), max(num_list)
				1593	</pre></div></div></li>
				1594
				1595	<li>
				1596	<p>Gets the min/max value of numeric items in the given list.</p></li>
				1597
				1598	<li>Arguments:
				1599
				1600	<ul>
				1601
				1602	<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>
				1603	</ul></li>
				1604
				1605	<li>Return Value:
				1606
				1607	<ul>
				1608
				1609	<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>
				1610	</ul></li>
				1611
				1612	<li>
				1613	<p>Example:</p>
				1614
				1615	<div class="source">
				1616	<div class="source">
				1617	<pre>use dataverse TinySocial;
				1618
				1619	let $l := for $i in dataset TwitterUsers return $i. friends_count
				1620	return {"min_friend_count": min($l), "max_friend_count": max($l)}
				1621	</pre></div></div></li>
				1622
				1623	<li>
				1624	<p>The expected result is:</p>
				1625
				1626	<div class="source">
				1627	<div class="source">
				1628	<pre>{ "min_friend_count": 18, "max_friend_count": 445 }
				1629	</pre></div></div></li>
				1630	</ul></div>
				1631	<div class="section">
				1632	<h3><a name="sql-count"></a>sql-count</h3>
				1633
				1634	<ul>
				1635
				1636	<li>
				1637	<p>Syntax:</p>
				1638
				1639	<div class="source">
				1640	<div class="source">
				1641	<pre>sql-count(list)
				1642	</pre></div></div></li>
				1643
				1644	<li>
				1645	<p>Gets the number of non-null items in the given list.</p></li>
				1646
				1647	<li>Arguments:
				1648
				1649	<ul>
				1650
				1651	<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>
				1652	</ul></li>
				1653
				1654	<li>Return Value:
				1655
				1656	<ul>
				1657
				1658	<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>
				1659	</ul></li>
				1660
				1661	<li>
				1662	<p>Example:</p></li>
				1663	</ul>
				1664
				1665	<div class="source">
				1666	<div class="source">
				1667	<pre> let $l1 := ['hello', 'world', 1, 2, 3, null]
				1668	return {"count": sql-count($l1)}
				1669	</pre></div></div>
				1670
				1671	<ul>
				1672
				1673	<li>
				1674	<p>The expected result is:</p>
				1675
				1676	<div class="source">
				1677	<div class="source">
				1678	<pre>{ "count": 5i64 }
				1679	</pre></div></div></li>
				1680	</ul></div>
				1681	<div class="section">
				1682	<h3><a name="sql-avg"></a>sql-avg</h3>
				1683
				1684	<ul>
				1685
				1686	<li>
				1687	<p>Syntax:</p>
				1688
				1689	<div class="source">
				1690	<div class="source">
				1691	<pre>sql-avg(num_list)
				1692	</pre></div></div></li>
				1693
				1694	<li>
				1695	<p>Gets the average value of the non-null items in the given list.</p></li>
				1696
				1697	<li>Arguments:
				1698
				1699	<ul>
				1700
				1701	<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>
				1702	</ul></li>
				1703
				1704	<li>Return Value:
				1705
				1706	<ul>
				1707
				1708	<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>
				1709	</ul></li>
				1710
				1711	<li>
				1712	<p>Example:</p>
				1713
				1714	<div class="source">
				1715	<div class="source">
				1716	<pre>let $l := [1.2, 2.3, 3.4, 0, null]
				1717	return {"avg": sql-avg($l)}
				1718	</pre></div></div></li>
				1719
				1720	<li>
				1721	<p>The expected result is:</p>
				1722
				1723	<div class="source">
				1724	<div class="source">
				1725	<pre>{ "avg": 1.725d }
				1726	</pre></div></div></li>
				1727	</ul></div>
				1728	<div class="section">
				1729	<h3><a name="sql-sum"></a>sql-sum</h3>
				1730
				1731	<ul>
				1732
				1733	<li>
				1734	<p>Syntax:</p>
				1735
				1736	<div class="source">
				1737	<div class="source">
				1738	<pre>sql-sum(num_list)
				1739	</pre></div></div></li>
				1740
				1741	<li>
				1742	<p>Gets the sum of the non-null items in the given list.</p></li>
				1743
				1744	<li>Arguments:
				1745
				1746	<ul>
				1747
				1748	<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>
				1749	</ul></li>
				1750
				1751	<li>Return Value:
				1752
				1753	<ul>
				1754
				1755	<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>
				1756	</ul></li>
				1757
				1758	<li>
				1759	<p>Example:</p>
				1760
				1761	<div class="source">
				1762	<div class="source">
				1763	<pre>let $l := [1.2, 2.3, 3.4, 0, null]
				1764	return {"sum": sql-sum($l)}
				1765	</pre></div></div></li>
				1766
				1767	<li>
				1768	<p>The expected result is:</p>
				1769
				1770	<div class="source">
				1771	<div class="source">
				1772	<pre>{ "sum": 6.9d }
				1773	</pre></div></div></li>
				1774	</ul></div>
				1775	<div class="section">
				1776	<h3><a name="sql-minmax"></a>sql-min/max</h3>
				1777
				1778	<ul>
				1779
				1780	<li>
				1781	<p>Syntax:</p>
				1782
				1783	<div class="source">
				1784	<div class="source">
				1785	<pre>sql-min(num_list), sql-max(num_list)
				1786	</pre></div></div></li>
				1787
				1788	<li>
				1789	<p>Gets the min/max value of the non-null numeric items in the given list.</p></li>
				1790
				1791	<li>Arguments:
				1792
				1793	<ul>
				1794
				1795	<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>
				1796	</ul></li>
				1797
				1798	<li>Return Value:
				1799
				1800	<ul>
				1801
				1802	<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>
				1803	</ul></li>
				1804
				1805	<li>
				1806	<p>Example:</p>
				1807
				1808	<div class="source">
				1809	<div class="source">
				1810	<pre>let $l := [1.2, 2.3, 3.4, 0, null]
				1811	return {"min": sql-min($l), "max": sql-max($l)}
				1812	</pre></div></div></li>
				1813
				1814	<li>
				1815	<p>The expected result is:</p>
				1816
				1817	<div class="source">
				1818	<div class="source">
				1819	<pre>{ "min": 0.0d, "max": 3.4d }
				1820	</pre></div></div></li>
				1821	</ul></div></div>
				1822	<div class="section">
				1823	<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>
				1824	<div class="section">
				1825	<h3><a name="create-point"></a>create-point</h3>
				1826
				1827	<ul>
				1828
				1829	<li>
				1830	<p>Syntax:</p>
				1831
				1832	<div class="source">
				1833	<div class="source">
				1834	<pre>create-point(x, y)
				1835	</pre></div></div></li>
				1836
				1837	<li>
				1838	<p>Creates the primitive type <tt>point</tt> using an <tt>x</tt> and <tt>y</tt> value.</p></li>
				1839
				1840	<li>Arguments:</li>
				1841
				1842	<li><tt>x</tt> : A <tt>double</tt> that represents the x-coordinate.</li>
				1843
				1844	<li><tt>y</tt> : A <tt>double</tt> that represents the y-coordinate.</li>
				1845
				1846	<li>Return Value:</li>
				1847
				1848	<li>A <tt>point</tt> representing the ordered pair (<tt>x</tt>, <tt>y</tt>).</li>
				1849
				1850	<li>
				1851	<p>Example:</p>
				1852
				1853	<div class="source">
				1854	<div class="source">
				1855	<pre>use dataverse TinySocial;
				1856
				1857	let $c := create-point(30.0,70.0)
				1858	return {"point": $c}
				1859	</pre></div></div></li>
				1860	</ul>
				1861
				1862	<ul>
				1863
				1864	<li>
				1865	<p>The expected result is:</p>
				1866
				1867	<div class="source">
				1868	<div class="source">
				1869	<pre>{ "point": point("30.0,70.0") }
				1870	</pre></div></div></li>
				1871	</ul></div>
				1872	<div class="section">
				1873	<h3><a name="create-line"></a>create-line</h3>
				1874
				1875	<ul>
				1876
				1877	<li>
				1878	<p>Syntax:</p>
				1879
				1880	<div class="source">
				1881	<div class="source">
				1882	<pre>create-line(point_expression1, point_expression2)
				1883	</pre></div></div></li>
				1884
				1885	<li>
				1886	<p>Creates the primitive type <tt>line</tt> using <tt>point_expression1</tt> and <tt>point_expression2</tt>.</p></li>
				1887
				1888	<li>Arguments:
				1889
				1890	<ul>
				1891
				1892	<li><tt>point_expression1</tt> : A <tt>point</tt> that represents the start point of the line.</li>
				1893
				1894	<li><tt>point_expression2</tt> : A <tt>point</tt> that represents the end point of the line.</li>
				1895	</ul></li>
				1896
				1897	<li>Return Value:
				1898
				1899	<ul>
				1900
				1901	<li>A spatial <tt>line</tt> created using the points provided in <tt>point_expression1</tt> and <tt>point_expression2</tt>.</li>
				1902	</ul></li>
				1903
				1904	<li>
				1905	<p>Example:</p>
				1906
				1907	<div class="source">
				1908	<div class="source">
				1909	<pre>use dataverse TinySocial;
				1910
				1911	let $c := create-line(create-point(30.0,70.0), create-point(50.0,90.0))
				1912	return {"line": $c}
				1913	</pre></div></div></li>
				1914	</ul>
				1915
				1916	<ul>
				1917
				1918	<li>
				1919	<p>The expected result is:</p>
				1920
				1921	<div class="source">
				1922	<div class="source">
				1923	<pre>{ "line": line("30.0,70.0 50.0,90.0") }
				1924	</pre></div></div></li>
				1925	</ul></div>
				1926	<div class="section">
				1927	<h3><a name="create-rectangle"></a>create-rectangle</h3>
				1928
				1929	<ul>
				1930
				1931	<li>
				1932	<p>Syntax:</p>
				1933
				1934	<div class="source">
				1935	<div class="source">
				1936	<pre>create-rectangle(point_expression1, point_expression2)
				1937	</pre></div></div></li>
				1938
				1939	<li>
				1940	<p>Creates the primitive type <tt>rectangle</tt> using <tt>point_expression1</tt> and <tt>point_expression2</tt>.</p></li>
				1941
				1942	<li>Arguments:
				1943
				1944	<ul>
				1945
				1946	<li><tt>point_expression1</tt> : A <tt>point</tt> that represents the lower-left point of the rectangle.</li>
				1947
				1948	<li><tt>point_expression2</tt> : A <tt>point</tt> that represents the upper-right point of the rectangle.</li>
				1949	</ul></li>
				1950
				1951	<li>Return Value:
				1952
				1953	<ul>
				1954
				1955	<li>A spatial <tt>rectangle</tt> created using the points provided in <tt>point_expression1</tt> and <tt>point_expression2</tt>.</li>
				1956	</ul></li>
				1957
				1958	<li>
				1959	<p>Example:</p>
				1960
				1961	<div class="source">
				1962	<div class="source">
				1963	<pre>use dataverse TinySocial;
				1964
				1965	let $c := create-rectangle(create-point(30.0,70.0), create-point(50.0,90.0))
				1966	return {"rectangle": $c}
				1967	</pre></div></div></li>
				1968	</ul>
				1969
				1970	<ul>
				1971
				1972	<li>
				1973	<p>The expected result is:</p>
				1974
				1975	<div class="source">
				1976	<div class="source">
				1977	<pre>{ "rectangle": rectangle("30.0,70.0 50.0,90.0") }
				1978	</pre></div></div></li>
				1979	</ul></div>
				1980	<div class="section">
				1981	<h3><a name="create-circle"></a>create-circle</h3>
				1982
				1983	<ul>
				1984
				1985	<li>
				1986	<p>Syntax:</p>
				1987
				1988	<div class="source">
				1989	<div class="source">
				1990	<pre>create-circle(point_expression, radius)
				1991	</pre></div></div></li>
				1992
				1993	<li>
				1994	<p>Creates the primitive type <tt>circle</tt> using <tt>point_expression</tt> and <tt>radius</tt>.</p></li>
				1995
				1996	<li>Arguments:
				1997
				1998	<ul>
				1999
				2000	<li><tt>point_expression</tt> : A <tt>point</tt> that represents the center of the circle.</li>
				2001
				2002	<li><tt>radius</tt> : A <tt>double</tt> that represents the radius of the circle.</li>
				2003	</ul></li>
				2004
				2005	<li>Return Value:
				2006
				2007	<ul>
				2008
				2009	<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>
				2010	</ul></li>
				2011
				2012	<li>
				2013	<p>Example:</p>
				2014
				2015	<div class="source">
				2016	<div class="source">
				2017	<pre>use dataverse TinySocial;
				2018
				2019	let $c := create-circle(create-point(30.0,70.0), 5.0)
				2020	return {"circle": $c}
				2021	</pre></div></div></li>
				2022	</ul>
				2023
				2024	<ul>
				2025
				2026	<li>
				2027	<p>The expected result is:</p>
				2028
				2029	<div class="source">
				2030	<div class="source">
				2031	<pre>{ "circle": circle("30.0,70.0 5.0") }
				2032	</pre></div></div></li>
				2033	</ul></div>
				2034	<div class="section">
				2035	<h3><a name="create-polygon"></a>create-polygon</h3>
				2036
				2037	<ul>
				2038
				2039	<li>
				2040	<p>Syntax:</p>
				2041
				2042	<div class="source">
				2043	<div class="source">
				2044	<pre>create-polygon(list_expression)
				2045	</pre></div></div></li>
				2046
				2047	<li>
				2048	<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>
				2049
				2050	<li>Arguments:</li>
				2051
				2052	<li><tt>list_expression</tt> : An OrderedList of doubles representing the points of the polygon.</li>
				2053
				2054	<li>Return Value:</li>
				2055
				2056	<li>A <tt>polygon</tt>, represents a spatial simple polygon created using the points provided in <tt>list_expression</tt>.</li>
				2057
				2058	<li>
				2059	<p>Example:</p>
				2060
				2061	<div class="source">
				2062	<div class="source">
				2063	<pre>use dataverse TinySocial;
				2064
				2065	let $c := create-polygon([1.0,1.0,2.0,2.0,3.0,3.0,4.0,4.0])
				2066	return {"polygon": $c}
				2067	</pre></div></div></li>
				2068	</ul>
				2069
				2070	<ul>
				2071
				2072	<li>
				2073	<p>The expected result is:</p>
				2074
				2075	<div class="source">
				2076	<div class="source">
				2077	<pre>{ "polygon": polygon("1.0,1.0 2.0,2.0 3.0,3.0 4.0,4.0") }
				2078	</pre></div></div></li>
				2079	</ul></div>
				2080	<div class="section">
				2081	<h3><a name="get-xget-y"></a>get-x/get-y</h3>
				2082
				2083	<ul>
				2084
				2085	<li>
				2086	<p>Syntax:</p>
				2087
				2088	<div class="source">
				2089	<div class="source">
				2090	<pre>get-x(point_expression) or get-y(point_expression)
				2091	</pre></div></div></li>
				2092
				2093	<li>
				2094	<p>Returns the x or y coordinates of a point <tt>point_expression</tt>.</p></li>
				2095
				2096	<li>Arguments:
				2097
				2098	<ul>
				2099
				2100	<li><tt>point_expression</tt> : A <tt>point</tt>.</li>
				2101	</ul></li>
				2102
				2103	<li>Return Value:
				2104
				2105	<ul>
				2106
				2107	<li>A <tt>double</tt> representing the x or y coordinates of the point <tt>point_expression</tt>.</li>
				2108	</ul></li>
				2109
				2110	<li>
				2111	<p>Example:</p>
				2112
				2113	<div class="source">
				2114	<div class="source">
				2115	<pre>use dataverse TinySocial;
				2116
				2117	let $point := create-point(2.3,5.0)
				2118	return {"x-coordinate": get-x($point), "y-coordinate": get-y($point)}
				2119	</pre></div></div></li>
				2120	</ul>
				2121
				2122	<ul>
				2123
				2124	<li>
				2125	<p>The expected result is:</p>
				2126
				2127	<div class="source">
				2128	<div class="source">
				2129	<pre>{ "x-coordinate": 2.3d, "y-coordinate": 5.0d }
				2130	</pre></div></div></li>
				2131	</ul></div>
				2132	<div class="section">
				2133	<h3><a name="get-points"></a>get-points</h3>
				2134
				2135	<ul>
				2136
				2137	<li>
				2138	<p>Syntax:</p>
				2139
				2140	<div class="source">
				2141	<div class="source">
				2142	<pre>get-points(spatial_expression)
				2143	</pre></div></div></li>
				2144
				2145	<li>
				2146	<p>Returns an ordered list of the points forming the spatial object <tt>spatial_expression</tt>.</p></li>
				2147
				2148	<li>Arguments:
				2149
				2150	<ul>
				2151
				2152	<li><tt>spatial_expression</tt> : A <tt>point</tt>, <tt>line</tt>, <tt>rectangle</tt>, <tt>circle</tt>, or <tt>polygon</tt>.</li>
				2153	</ul></li>
				2154
				2155	<li>Return Value:
				2156
				2157	<ul>
				2158
				2159	<li>An <tt>OrderedList</tt> of the points forming the spatial object <tt>spatial_expression</tt>.</li>
				2160	</ul></li>
				2161
				2162	<li>
				2163	<p>Example:</p>
				2164
				2165	<div class="source">
				2166	<div class="source">
				2167	<pre>use dataverse TinySocial;
				2168
				2169	let $line := create-line(create-point(100.6,99.4), create-point(-72.0,-76.9))
				2170	let $rectangle := create-rectangle(create-point(9.2,49.0), create-point(77.8,111.1))
				2171	let $polygon := create-polygon([1.0,1.0,2.0,2.0,3.0,3.0,4.0,4.0])
				2172	let $line_list := get-points($line)
				2173	let $rectangle_list := get-points($rectangle)
				2174	let $polygon_list := get-points($polygon)
				2175	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]}
				2176	</pre></div></div></li>
				2177	</ul>
				2178
				2179	<ul>
				2180
				2181	<li>
				2182	<p>The expected result is:</p>
				2183
				2184	<div class="source">
				2185	<div class="source">
				2186	<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") }
				2187	</pre></div></div></li>
				2188	</ul></div>
				2189	<div class="section">
				2190	<h3><a name="get-centerget-radius"></a>get-center/get-radius</h3>
				2191
				2192	<ul>
				2193
				2194	<li>
				2195	<p>Syntax:</p>
				2196
				2197	<div class="source">
				2198	<div class="source">
				2199	<pre>get-center(circle_expression) or get-radius(circle_expression)
				2200	</pre></div></div></li>
				2201
				2202	<li>
				2203	<p>Returns the center and the radius of a circle <tt>circle_expression</tt>, respectively.</p></li>
				2204
				2205	<li>Arguments:
				2206
				2207	<ul>
				2208
				2209	<li><tt>circle_expression</tt> : A <tt>circle</tt>.</li>
				2210	</ul></li>
				2211
				2212	<li>Return Value:
				2213
				2214	<ul>
				2215
				2216	<li>A <tt>point</tt> or <tt>double</tt>, represent the center or radius of the circle <tt>circle_expression</tt>.</li>
				2217	</ul></li>
				2218
				2219	<li>
				2220	<p>Example:</p>
				2221
				2222	<div class="source">
				2223	<div class="source">
				2224	<pre>use dataverse TinySocial;
				2225
				2226	let $circle := create-circle(create-point(6.0,3.0), 1.0)
				2227	return {"circle-radius": get-radius($circle), "circle-center": get-center($circle)}
				2228	</pre></div></div></li>
				2229	</ul>
				2230
				2231	<ul>
				2232
				2233	<li>
				2234	<p>The expected result is:</p>
				2235
				2236	<div class="source">
				2237	<div class="source">
				2238	<pre>{ "circle-radius": 1.0d, "circle-center": point("6.0,3.0") }
				2239	</pre></div></div></li>
				2240	</ul></div>
				2241	<div class="section">
				2242	<h3><a name="spatial-distance"></a>spatial-distance</h3>
				2243
				2244	<ul>
				2245
				2246	<li>
				2247	<p>Syntax:</p>
				2248
				2249	<div class="source">
				2250	<div class="source">
				2251	<pre>spatial-distance(point_expression1, point_expression2)
				2252	</pre></div></div></li>
				2253
				2254	<li>
				2255	<p>Returns the Euclidean distance between <tt>point_expression1</tt> and <tt>point_expression2</tt>.</p></li>
				2256
				2257	<li>Arguments:
				2258
				2259	<ul>
				2260
				2261	<li><tt>point_expression1</tt> : A <tt>point</tt>.</li>
				2262
				2263	<li><tt>point_expression2</tt> : A <tt>point</tt>.</li>
				2264	</ul></li>
				2265
				2266	<li>Return Value:
				2267
				2268	<ul>
				2269
				2270	<li>A <tt>double</tt> as the Euclidean distance between <tt>point_expression1</tt> and <tt>point_expression2</tt>.</li>
				2271	</ul></li>
				2272
				2273	<li>
				2274	<p>Example:</p>
				2275
				2276	<div class="source">
				2277	<div class="source">
				2278	<pre>use dataverse TinySocial;
				2279
				2280	for $t in dataset('TweetMessages')
				2281	let $d := spatial-distance($t.sender-location, create-point(30.0,70.0))
				2282	return {"point": $t.sender-location, "distance": $d}
				2283	</pre></div></div></li>
				2284	</ul>
				2285
				2286	<ul>
				2287
				2288	<li>
				2289	<p>The expected result is:</p>
				2290
				2291	<div class="source">
				2292	<div class="source">
				2293	<pre>{ "point": point("47.44,80.65"), "distance": 20.434678857275934d }
				2294	{ "point": point("29.15,76.53"), "distance": 6.585089217315132d }
				2295	{ "point": point("37.59,68.42"), "distance": 7.752709203884797d }
				2296	{ "point": point("24.82,94.63"), "distance": 25.168816023007512d }
				2297	{ "point": point("32.84,67.14"), "distance": 4.030533463451212d }
				2298	{ "point": point("29.72,75.8"), "distance": 5.806754687430835d }
				2299	{ "point": point("39.28,70.48"), "distance": 9.292405501268227d }
				2300	{ "point": point("40.09,92.69"), "distance": 24.832321679617472d }
				2301	{ "point": point("47.51,83.99"), "distance": 22.41250097601782d }
				2302	{ "point": point("36.21,72.6"), "distance": 6.73231758015024d }
				2303	{ "point": point("46.05,93.34"), "distance": 28.325926286707734d }
				2304	{ "point": point("36.86,74.62"), "distance": 8.270671073135482d }
				2305	</pre></div></div></li>
				2306	</ul></div>
				2307	<div class="section">
				2308	<h3><a name="spatial-area"></a>spatial-area</h3>
				2309
				2310	<ul>
				2311
				2312	<li>
				2313	<p>Syntax:</p>
				2314
				2315	<div class="source">
				2316	<div class="source">
				2317	<pre>spatial-area(spatial_2d_expression)
				2318	</pre></div></div></li>
				2319
				2320	<li>
				2321	<p>Returns the spatial area of <tt>spatial_2d_expression</tt>.</p></li>
				2322
				2323	<li>Arguments:
				2324
				2325	<ul>
				2326
				2327	<li><tt>spatial_2d_expression</tt> : A <tt>rectangle</tt>, <tt>circle</tt>, or <tt>polygon</tt>.</li>
				2328	</ul></li>
				2329
				2330	<li>Return Value:
				2331
				2332	<ul>
				2333
				2334	<li>A <tt>double</tt> representing the area of <tt>spatial_2d_expression</tt>.</li>
				2335	</ul></li>
				2336
				2337	<li>
				2338	<p>Example:</p>
				2339
				2340	<div class="source">
				2341	<div class="source">
				2342	<pre>use dataverse TinySocial;
				2343
				2344	let $circleArea := spatial-area(create-circle(create-point(0.0,0.0), 5.0))
				2345	return {"Area":$circleArea}
				2346	</pre></div></div></li>
				2347	</ul>
				2348
				2349	<ul>
				2350
				2351	<li>
				2352	<p>The expected result is:</p>
				2353
				2354	<div class="source">
				2355	<div class="source">
				2356	<pre>{ "Area": 78.53981625d }
				2357	</pre></div></div></li>
				2358	</ul></div>
				2359	<div class="section">
				2360	<h3><a name="spatial-intersect"></a>spatial-intersect</h3>
				2361
				2362	<ul>
				2363
				2364	<li>
				2365	<p>Syntax:</p>
				2366
				2367	<div class="source">
				2368	<div class="source">
				2369	<pre>spatial-intersect(spatial_expression1, spatial_expression2)
				2370	</pre></div></div></li>
				2371
				2372	<li>
				2373	<p>Checks whether <tt>@arg1</tt> and <tt>@arg2</tt> spatially intersect each other.</p></li>
				2374
				2375	<li>Arguments:
				2376
				2377	<ul>
				2378
				2379	<li><tt>spatial_expression1</tt> : A <tt>point</tt>, <tt>line</tt>, <tt>rectangle</tt>, <tt>circle</tt>, or <tt>polygon</tt>.</li>
				2380
				2381	<li><tt>spatial_expression2</tt> : A <tt>point</tt>, <tt>line</tt>, <tt>rectangle</tt>, <tt>circle</tt>, or <tt>polygon</tt>.</li>
				2382	</ul></li>
				2383
				2384	<li>Return Value:
				2385
				2386	<ul>
				2387
				2388	<li>A <tt>boolean</tt> representing whether <tt>spatial_expression1</tt> and <tt>spatial_expression2</tt> spatially overlap with each other.</li>
				2389	</ul></li>
				2390
				2391	<li>
				2392	<p>Example:</p>
				2393
				2394	<div class="source">
				2395	<div class="source">
				2396	<pre>use dataverse TinySocial;
				2397
				2398	for $t in dataset('TweetMessages')
				2399	where spatial-intersect($t.sender-location, create-rectangle(create-point(30.0,70.0), create-point(40.0,80.0)))
				2400	return $t
				2401	</pre></div></div></li>
				2402	</ul>
				2403
				2404	<ul>
				2405
				2406	<li>
				2407	<p>The expected result is:</p>
				2408
				2409	<div class="source">
				2410	<div class="source">
				2411	<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:)" }
				2412	{ "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" }
				2413	{ "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" }
				2414	</pre></div></div></li>
				2415	</ul></div>
				2416	<div class="section">
				2417	<h3><a name="spatial-cell"></a>spatial-cell</h3>
				2418
				2419	<ul>
				2420
				2421	<li>
				2422	<p>Syntax:</p>
				2423
				2424	<div class="source">
				2425	<div class="source">
				2426	<pre>spatial-cell(point_expression1, point_expression2, x_increment, y_increment)
				2427	</pre></div></div></li>
				2428
				2429	<li>
				2430	<p>Returns the grid cell that <tt>point_expression1</tt> belongs to.</p></li>
				2431
				2432	<li>Arguments:
				2433
				2434	<ul>
				2435
				2436	<li><tt>point_expression1</tt> : A <tt>point</tt> representing the point of interest that its grid cell will be returned.</li>
				2437
				2438	<li><tt>point_expression2</tt> : A <tt>point</tt> representing the origin of the grid.</li>
				2439
				2440	<li><tt>x_increment</tt> : A <tt>double</tt>, represents X increments.</li>
				2441
				2442	<li><tt>y_increment</tt> : A <tt>double</tt>, represents Y increments.</li>
				2443	</ul></li>
				2444
				2445	<li>Return Value:
				2446
				2447	<ul>
				2448
				2449	<li>A <tt>rectangle</tt> representing the grid cell that <tt>point_expression1</tt> belongs to.</li>
				2450	</ul></li>
				2451
				2452	<li>
				2453	<p>Example:</p>
				2454
				2455	<div class="source">
				2456	<div class="source">
				2457	<pre>use dataverse TinySocial;
				2458
				2459	for $t in dataset('TweetMessages')
				2460	group by $c := spatial-cell($t.sender-location, create-point(20.0,50.0), 5.5, 6.0) with $t
				2461	let $num := count($t)
				2462	return { "cell": $c, "count": $num}
				2463	</pre></div></div></li>
				2464	</ul>
				2465
				2466	<ul>
				2467
				2468	<li>
				2469	<p>The expected result is:</p>
				2470
				2471	<div class="source">
				2472	<div class="source">
				2473	<pre>{ "cell": rectangle("20.0,92.0 25.5,98.0"), "count": 1i64 }
				2474	{ "cell": rectangle("25.5,74.0 31.0,80.0"), "count": 2i64 }
				2475	{ "cell": rectangle("31.0,62.0 36.5,68.0"), "count": 1i64 }
				2476	{ "cell": rectangle("31.0,68.0 36.5,74.0"), "count": 1i64 }
				2477	{ "cell": rectangle("36.5,68.0 42.0,74.0"), "count": 2i64 }
				2478	{ "cell": rectangle("36.5,74.0 42.0,80.0"), "count": 1i64 }
				2479	{ "cell": rectangle("36.5,92.0 42.0,98.0"), "count": 1i64 }
				2480	{ "cell": rectangle("42.0,80.0 47.5,86.0"), "count": 1i64 }
				2481	{ "cell": rectangle("42.0,92.0 47.5,98.0"), "count": 1i64 }
				2482	{ "cell": rectangle("47.5,80.0 53.0,86.0"), "count": 1i64 }
				2483	</pre></div></div></li>
				2484	</ul></div></div>
				2485	<div class="section">
				2486	<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>
				2487	<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>
				2488	<div class="section">
				2489	<h3><a name="edit-distance"></a>edit-distance</h3>
				2490
				2491	<ul>
				2492
				2493	<li>
				2494	<p>Syntax:</p>
				2495
				2496	<div class="source">
				2497	<div class="source">
				2498	<pre>edit-distance(expression1, expression2)
				2499	</pre></div></div></li>
				2500
				2501	<li>
				2502	<p>Returns the edit distance of <tt>expression1</tt> and <tt>expression2</tt>.</p></li>
				2503
				2504	<li>Arguments:
				2505
				2506	<ul>
				2507
				2508	<li><tt>expression1</tt> : A <tt>string</tt> or a homogeneous <tt>OrderedList</tt> of a comparable item type.</li>
				2509
				2510	<li><tt>expression2</tt> : The same type as <tt>expression1</tt>.</li>
				2511	</ul></li>
				2512
				2513	<li>Return Value:
				2514
				2515	<ul>
				2516
				2517	<li>An <tt>int64</tt> that represents the edit distance between <tt>expression1</tt> and <tt>expression2</tt>.</li>
				2518	</ul></li>
				2519
				2520	<li>Note: An <a href="similarity.html#UsingIndexesToSupportSimilarityQueries">n-gram index</a> can be utilized for this function.</li>
				2521
				2522	<li>
				2523	<p>Example:</p>
				2524
				2525	<div class="source">
				2526	<div class="source">
				2527	<pre>use dataverse TinySocial;
				2528
				2529	for $user in dataset('FacebookUsers')
				2530	let $ed := edit-distance($user.name, "Suzanna Tilson")
				2531	where $ed <= 2
				2532	return $user
				2533	</pre></div></div></li>
				2534	</ul>
				2535
				2536	<ul>
				2537
				2538	<li>
				2539	<p>The expected result is:</p>
				2540
				2541	<div class="source">
				2542	<div class="source">
				2543	<pre>{
				2544	"id": 7, "alias": "Suzanna", "name": "SuzannaTillson", "user-since": datetime("2012-08-07T10:10:00.000Z"), "friend-ids": {{ 6 }},
				2545	"employment": [ { "organization-name": "Labzatron", "start-date": date("2011-04-19"), "end-date": null } ]
				2546	}
				2547	</pre></div></div></li>
				2548	</ul></div>
				2549	<div class="section">
				2550	<h3><a name="edit-distance-check"></a>edit-distance-check</h3>
				2551
				2552	<ul>
				2553
				2554	<li>
				2555	<p>Syntax:</p>
				2556
				2557	<div class="source">
				2558	<div class="source">
				2559	<pre>edit-distance-check(expression1, expression2, threshold)
				2560	</pre></div></div></li>
				2561
				2562	<li>
				2563	<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>
				2564
				2565	<li>
				2566	<p>Arguments:</p>
				2567
				2568	<ul>
				2569
				2570	<li><tt>expression1</tt> : A <tt>string</tt> or a homogeneous <tt>OrderedList</tt> of a comparable item type.</li>
				2571
				2572	<li><tt>expression2</tt> : The same type as <tt>expression1</tt>.</li>
				2573
				2574	<li><tt>threshold</tt> : An <tt>int64</tt> that represents the distance threshold.</li>
				2575	</ul></li>
				2576
				2577	<li>Return Value:
				2578
				2579	<ul>
				2580
				2581	<li>An <tt>OrderedList</tt> with two items:
				2582
				2583	<ul>
				2584
				2585	<li>The first item contains a <tt>boolean</tt> value representing whether <tt>expression1</tt> and <tt>expression2</tt> are similar.</li>
				2586
				2587	<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>
				2588	</ul></li>
				2589	</ul></li>
				2590
				2591	<li>Note: An <a href="similarity.html#UsingIndexesToSupportSimilarityQueries">n-gram index</a> can be utilized for this function.</li>
				2592
				2593	<li>
				2594	<p>Example:</p>
				2595
				2596	<div class="source">
				2597	<div class="source">
				2598	<pre>use dataverse TinySocial;
				2599
				2600	for $user in dataset('FacebookUsers')
				2601	let $ed := edit-distance-check($user.name, "Suzanna Tilson", 2)
				2602	where $ed[0]
				2603	return $ed[1]
				2604	</pre></div></div></li>
				2605	</ul>
				2606
				2607	<ul>
				2608
				2609	<li>
				2610	<p>The expected result is:</p>
				2611
				2612	<div class="source">
				2613	<div class="source">
				2614	<pre>2
				2615	</pre></div></div></li>
				2616	</ul></div>
				2617	<div class="section">
				2618	<h3><a name="edit-distance-contains"></a>edit-distance-contains</h3>
				2619
				2620	<ul>
				2621
				2622	<li>Syntax:</li>
				2623	</ul>
				2624	<p>edit-distance-contains(expression1, expression2, threshold)</p>
				2625
				2626	<ul>
				2627
				2628	<li>
				2629	<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>
				2630
				2631	<li>
				2632	<p>Arguments:</p>
				2633
				2634	<ul>
				2635
				2636	<li><tt>expression1</tt> : A <tt>string</tt> or a homogeneous <tt>OrderedList</tt> of a comparable item type.</li>
				2637
				2638	<li><tt>expression2</tt> : The same type as <tt>expression1</tt>.</li>
				2639
				2640	<li><tt>threshold</tt> : An <tt>int32</tt> that represents the distance threshold.</li>
				2641	</ul></li>
				2642
				2643	<li>Return Value:
				2644
				2645	<ul>
				2646
				2647	<li>An <tt>OrderedList</tt> with two items:
				2648
				2649	<ul>
				2650
				2651	<li>The first item contains a <tt>boolean</tt> value representing whether <tt>expression1</tt> can contain <tt>expression2</tt>.</li>
				2652
				2653	<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>
				2654	</ul></li>
				2655	</ul></li>
				2656
				2657	<li>Note: An <a href="similarity.html#UsingIndexesToSupportSimilarityQueries">n-gram index</a> can be utilized for this function.</li>
				2658
				2659	<li>
				2660	<p>Example:</p>
				2661
				2662	<div class="source">
				2663	<div class="source">
				2664	<pre>let $i := edit-distance-contains("happy","hapr",2)
				2665	return $i;
				2666	</pre></div></div></li>
				2667	</ul>
				2668
				2669	<ul>
				2670
				2671	<li>
				2672	<p>The expected result is:</p>
				2673
				2674	<div class="source">
				2675	<div class="source">
				2676	<pre>[ true, 1 ]
				2677	</pre></div></div></li>
				2678	</ul></div>
				2679	<div class="section">
				2680	<h3><a name="similarity-jaccard"></a>similarity-jaccard</h3>
				2681
				2682	<ul>
				2683
				2684	<li>
				2685	<p>Syntax:</p>
				2686
				2687	<div class="source">
				2688	<div class="source">
				2689	<pre>similarity-jaccard(list_expression1, list_expression2)
				2690	</pre></div></div></li>
				2691
				2692	<li>
				2693	<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>
				2694
				2695	<li>Arguments:
				2696
				2697	<ul>
				2698
				2699	<li><tt>list_expression1</tt> : An <tt>UnorderedList</tt> or <tt>OrderedList</tt>.</li>
				2700
				2701	<li><tt>list_expression2</tt> : An <tt>UnorderedList</tt> or <tt>OrderedList</tt>.</li>
				2702	</ul></li>
				2703
				2704	<li>Return Value:
				2705
				2706	<ul>
				2707
				2708	<li>A <tt>float</tt> that represents the Jaccard similarity of <tt>list_expression1</tt> and <tt>list_expression2</tt>.</li>
				2709	</ul></li>
				2710
				2711	<li>Note: A <a href="similarity.html#UsingIndexesToSupportSimilarityQueries">keyword index</a> can be utilized for this function.</li>
				2712
				2713	<li>
				2714	<p>Example:</p>
				2715
				2716	<div class="source">
				2717	<div class="source">
				2718	<pre>use dataverse TinySocial;
				2719
				2720	for $user in dataset('FacebookUsers')
				2721	let $sim := similarity-jaccard($user.friend-ids, [1,5,9,10])
				2722	where $sim >= 0.6f
				2723	return $user
				2724	</pre></div></div></li>
				2725	</ul>
				2726
				2727	<ul>
				2728
				2729	<li>
				2730	<p>The expected result is:</p>
				2731
				2732	<div class="source">
				2733	<div class="source">
				2734	<pre>{
				2735	"id": 3, "alias": "Emory", "name": "EmoryUnk", "user-since": datetime("2012-07-10T10:10:00.000Z"), "friend-ids": {{ 1, 5, 8, 9 }},
				2736	"employment": [ { "organization-name": "geomedia", "start-date": date("2010-06-17"), "end-date": date("2010-01-26") } ]
				2737	}
				2738	{
				2739	"id": 10, "alias": "Bram", "name": "BramHatch", "user-since": datetime("2010-10-16T10:10:00.000Z"), "friend-ids": {{ 1, 5, 9 }},
				2740	"employment": [ { "organization-name": "physcane", "start-date": date("2007-06-05"), "end-date": date("2011-11-05") } ]
				2741	}
				2742	</pre></div></div></li>
				2743	</ul></div>
				2744	<div class="section">
				2745	<h3><a name="similarity-jaccard-check"></a>similarity-jaccard-check</h3>
				2746
				2747	<ul>
				2748
				2749	<li>
				2750	<p>Syntax:</p>
				2751
				2752	<div class="source">
				2753	<div class="source">
				2754	<pre>similarity-jaccard-check(list_expression1, list_expression2, threshold)
				2755	</pre></div></div></li>
				2756
				2757	<li>
				2758	<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>
				2759
				2760	<li>
				2761	<p>Arguments:</p>
				2762
				2763	<ul>
				2764
				2765	<li><tt>list_expression1</tt> : An <tt>UnorderedList</tt> or <tt>OrderedList</tt>.</li>
				2766
				2767	<li><tt>list_expression2</tt> : An <tt>UnorderedList</tt> or <tt>OrderedList</tt>.</li>
				2768
				2769	<li><tt>threshold</tt> : A <tt>float</tt> that represents the similarity threshold.</li>
				2770	</ul></li>
				2771
				2772	<li>Return Value:
				2773
				2774	<ul>
				2775
				2776	<li>An <tt>OrderedList</tt> with two items:</li>
				2777
				2778	<li>The first item contains a <tt>boolean</tt> value representing whether <tt>list_expression1</tt> and <tt>list_expression2</tt> are similar.</li>
				2779
				2780	<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>
				2781	</ul></li>
				2782
				2783	<li>Note: A <a href="similarity.html#UsingIndexesToSupportSimilarityQueries">keyword index</a> can be utilized for this function.</li>
				2784
				2785	<li>
				2786	<p>Example:</p>
				2787
				2788	<div class="source">
				2789	<div class="source">
				2790	<pre>use dataverse TinySocial;
				2791
				2792	for $user in dataset('FacebookUsers')
				2793	let $sim := similarity-jaccard-check($user.friend-ids, [1,5,9,10], 0.6f)
				2794	where $sim[0]
				2795	return $sim[1]
				2796	</pre></div></div></li>
				2797	</ul>
				2798
				2799	<ul>
				2800
				2801	<li>
				2802	<p>The expected result is:</p>
				2803
				2804	<div class="source">
				2805	<div class="source">
				2806	<pre>0.75f
				2807	1.0f
				2808	</pre></div></div></li>
				2809	</ul></div>
				2810	<div class="section">
				2811	<h3><a name="Similarity_Operator_"></a>Similarity Operator ~=</h3>
				2812
				2813	<ul>
				2814
				2815	<li>“<tt>~=</tt>” is syntactic sugar for expressing a similarity condition with a given similarity threshold.</li>
				2816
				2817	<li>The similarity function and threshold for “<tt>~=</tt>” are controlled via “set” directives.</li>
				2818
				2819	<li>The “<tt>~=</tt>” operator returns a <tt>boolean</tt> value that represents whether the operands are similar.</li>
				2820
				2821	<li>
				2822	<p>Example for Jaccard similarity:</p>
				2823
				2824	<div class="source">
				2825	<div class="source">
				2826	<pre>use dataverse TinySocial;
				2827
				2828	set simfunction "jaccard";
				2829	set simthreshold "0.6f";
				2830
				2831	for $user in dataset('FacebookUsers')
				2832	where $user.friend-ids ~= [1,5,9,10]
				2833	return $user
				2834	</pre></div></div></li>
				2835	</ul>
				2836
				2837	<ul>
				2838
				2839	<li>
				2840	<p>The expected result is:</p>
				2841
				2842	<div class="source">
				2843	<div class="source">
				2844	<pre>{
				2845	"id": 3, "alias": "Emory", "name": "EmoryUnk", "user-since": datetime("2012-07-10T10:10:00.000Z"), "friend-ids": {{ 1, 5, 8, 9 }},
				2846	"employment": [ { "organization-name": "geomedia", "start-date": date("2010-06-17"), "end-date": date("2010-01-26") } ]
				2847	}
				2848	{
				2849	"id": 10, "alias": "Bram", "name": "BramHatch", "user-since": datetime("2010-10-16T10:10:00.000Z"), "friend-ids": {{ 1, 5, 9 }},
				2850	"employment": [ { "organization-name": "physcane", "start-date": date("2007-06-05"), "end-date": date("2011-11-05") } ]
				2851	}
				2852	</pre></div></div></li>
				2853	</ul>
				2854
				2855	<ul>
				2856
				2857	<li>
				2858	<p>Example for edit-distance similarity:</p>
				2859
				2860	<div class="source">
				2861	<div class="source">
				2862	<pre>use dataverse TinySocial;
				2863
				2864	set simfunction "edit-distance";
				2865	set simthreshold "2";
				2866
				2867	for $user in dataset('FacebookUsers')
				2868	where $user.name ~= "Suzanna Tilson"
				2869	return $user
				2870	</pre></div></div></li>
				2871	</ul>
				2872
				2873	<ul>
				2874
				2875	<li>
				2876	<p>The expected output is:</p>
				2877
				2878	<div class="source">
				2879	<div class="source">
				2880	<pre>{
				2881	"id": 7, "alias": "Suzanna", "name": "SuzannaTillson", "user-since": datetime("2012-08-07T10:10:00.000Z"), "friend-ids": {{ 6 }},
				2882	"employment": [ { "organization-name": "Labzatron", "start-date": date("2011-04-19"), "end-date": null } ]
				2883	}
				2884	</pre></div></div></li>
				2885	</ul></div></div>
				2886	<div class="section">
				2887	<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>
				2888	<div class="section">
				2889	<h3><a name="word-tokens"></a>word-tokens</h3>
				2890
				2891	<ul>
				2892
				2893	<li>
				2894	<p>Syntax:</p>
				2895
				2896	<div class="source">
				2897	<div class="source">
				2898	<pre>word-tokens(string_expression)
				2899	</pre></div></div></li>
				2900
				2901	<li>
				2902	<p>Returns a list of word tokens of <tt>string_expression</tt> using non-alphanumeric characters as delimiters.</p></li>
				2903
				2904	<li>Arguments:
				2905
				2906	<ul>
				2907
				2908	<li><tt>string_expression</tt> : A <tt>string</tt> that will be tokenized.</li>
				2909	</ul></li>
				2910
				2911	<li>Return Value:
				2912
				2913	<ul>
				2914
				2915	<li>An <tt>OrderedList</tt> of <tt>string</tt> word tokens.</li>
				2916	</ul></li>
				2917
				2918	<li>
				2919	<p>Example:</p>
				2920
				2921	<div class="source">
				2922	<div class="source">
				2923	<pre>use dataverse TinySocial;
				2924
				2925	for $t in dataset('TweetMessages')
				2926	let $tokens := word-tokens($t.message-text)
				2927	where $t.send-time >= datetime('2012-01-01T00:00:00')
				2928	return {
				2929	"tweetid": $t.tweetid,
				2930	"word-tokens": $tokens
				2931	}
				2932	</pre></div></div></li>
				2933	</ul>
				2934
				2935	<ul>
				2936
				2937	<li>
				2938	<p>The expected result is:</p>
				2939
				2940	<div class="source">
				2941	<div class="source">
				2942	<pre>{ "tweetid": "9", "word-tokens": [ "love", "verizon", "its", "voicemail", "service", "is", "awesome" ] }
				2943	</pre></div></div></li>
				2944	</ul>
				2945	<!-- ### hashed-word-tokens ###
				2946	* Syntax:
				2947
				2948	hashed-word-tokens(string_expression)
				2949
				2950	* Returns a list of hashed word tokens of `string_expression`.
				2951	* Arguments:
				2952	* `string_expression` : A `string` that will be tokenized.
				2953	* Return Value:
				2954	* An `OrderedList` of `int32` hashed tokens.
				2955
				2956	* Example:
				2957
				2958	use dataverse TinySocial;
				2959
				2960	for $t in dataset('TweetMessages')
				2961	let $tokens := hashed-word-tokens($t.message-text)
				2962	where $t.send-time >= datetime('2012-01-01T00:00:00')
				2963	return {
				2964	"tweetid": $t.tweetid,
				2965	"hashed-word-tokens": $tokens
				2966	}
				2967
				2968
				2969	* The expected result is:
				2970
				2971	{ "tweetid": "9", "hashed-word-tokens": [ -1217719622, -447857469, -1884722688, -325178649, 210976949, 285049676, 1916743959 ] }
				2972
				2973
				2974	### counthashed-word-tokens ###
				2975	* Syntax:
				2976
				2977	counthashed-word-tokens(string_expression)
				2978
				2979	* 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.
				2980	* Arguments:
				2981	* `string_expression` : A `String` that will be tokenized.
				2982	* Return Value:
				2983	* An `OrderedList` of `Int32` hashed tokens.
				2984	* Example:
				2985
				2986	use dataverse TinySocial;
				2987
				2988	for $t in dataset('TweetMessages')
				2989	let $tokens := counthashed-word-tokens($t.message-text)
				2990	where $t.send-time >= datetime('2012-01-01T00:00:00')
				2991	return {
				2992	"tweetid": $t.tweetid,
				2993	"counthashed-word-tokens": $tokens
				2994	}
				2995
				2996
				2997	* The expected result is:
				2998
				2999	{ "tweetid": "9", "counthashed-word-tokens": [ -1217719622, -447857469, -1884722688, -325178649, 210976949, 285049676, 1916743959 ] }
				3000
				3001
				3002	### gram-tokens ###
				3003	* Syntax:
				3004
				3005	gram-tokens(string_expression, gram_length, boolean_expression)
				3006
				3007	* 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.
				3008	* Arguments:
				3009	* `string_expression` : A `String` that will be tokenized.
				3010	* `gram_length` : An `Int32` as the length of grams.
				3011	* `boolean_expression` : A `Boolean` value to indicate whether to generate additional grams by pre- and postfixing `string_expression` with special characters.
				3012	* Return Value:
				3013	* An `OrderedList` of String gram tokens.
				3014
				3015	* Example:
				3016
				3017	use dataverse TinySocial;
				3018
				3019	for $t in dataset('TweetMessages')
				3020	let $tokens := gram-tokens($t.message-text, 3, true)
				3021	where $t.send-time >= datetime('2012-01-01T00:00:00')
				3022	return {
				3023	"tweetid": $t.tweetid,
				3024	"gram-tokens": $tokens
				3025	}
				3026
				3027
				3028	* The expected result is:
				3029
				3030	{
				3031	"tweetid": "9",
				3032	"gram-tokens": [ "## ", "# l", " lo", "lov", "ove", "ve ", "e v", " ve", "ver", "eri", "riz", "izo", "zon", "on ", "n i", " it", "its", "ts ", "s v", " vo", "voi", "oic", "ice",
				3033	"cem", "ema", "mai", "ail", "il-", "l-s", "-se", "ser", "erv", "rvi", "vic", "ice", "ce ", "e i", " is", "is ", "s a", " aw", "awe", "wes", "eso", "som", "ome", "me$", "e$$" ]
				3034	}
				3035
				3036
				3037	### hashed-gram-tokens ###
				3038	* Syntax:
				3039
				3040	hashed-gram-tokens(string_expression, gram_length, boolean_expression)
				3041
				3042	* Returns a list of hashed gram tokens of `string_expression`.
				3043	* Arguments:
				3044	* `string_expression` : A `String` that will be tokenized.
				3045	* `gram_length` : An `Int32` as the length of grams.
				3046	* `boolean_expression` : A `Boolean` to indicate whether to generate additional grams by pre- and postfixing `string_expression` with special characters.
				3047	* Return Value:
				3048	* An `OrderedList` of `Int32` hashed gram tokens.
				3049
				3050	* Example:
				3051
				3052	use dataverse TinySocial;
				3053
				3054	for $t in dataset('TweetMessages')
				3055	let $tokens := hashed-gram-tokens($t.message-text, 3, true)
				3056	where $t.send-time >= datetime('2012-01-01T00:00:00')
				3057	return {
				3058	"tweetid": $t.tweetid,
				3059	"hashed-gram-tokens": $tokens
				3060	}
				3061
				3062
				3063	* The expected result is:
				3064
				3065	{
				3066	"tweetid": "9",
				3067	"hashed-gram-tokens": [ 40557178, -2002241593, 161665899, -856104603, -500544946, 693410611, 395674299, -1015235909, 1115608337, 1187999872, -31006095, -219180466, -1676061637,
				3068	1040194153, -1339307841, -1527110163, -1884722688, -179148713, -431014627, -1789789823, -1209719926, 684519765, -486734513, 1734740619, -1971673751, -932421915, -2064668066,
				3069	-937135958, -790946468, -69070309, 1561601454, 26169001, -160734571, 1330043462, -486734513, -18796768, -470303314, 113421364, 1615760212, 1688217556, 1223719184, 536568131,
				3070	1682609873, 2935161, -414769471, -1027490137, 1602276102, 1050490461 ]
				3071	}
				3072
				3073
				3074	### counthashed-gram-tokens ###
				3075	* Syntax:
				3076
				3077	counthashed-gram-tokens(string_expression, gram_length, boolean_expression)
				3078
				3079	* 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.
				3080	* Arguments:
				3081	* `string_expression` : A `String` that will be tokenized.
				3082	* `gram_length` : An `Int32`, length of grams to generate.
				3083	* `boolean_expression` : A `Boolean`, whether to generate additional grams by pre- and postfixing `string_expression` with special characters.
				3084	* Return Value:
				3085	* An `OrderedList` of `Int32` hashed gram tokens.
				3086
				3087	* Example:
				3088
				3089	use dataverse TinySocial;
				3090
				3091	for $t in dataset('TweetMessages')
				3092	let $tokens := counthashed-gram-tokens($t.message-text, 3, true)
				3093	where $t.send-time >= datetime('2012-01-01T00:00:00')
				3094	return {
				3095	"tweetid": $t.tweetid,
				3096	"counthashed-gram-tokens": $tokens
				3097	}
				3098
				3099
				3100	* The expected result is:
				3101
				3102	{
				3103	"tweetid": "9",
				3104	"counthashed-gram-tokens": [ 40557178, -2002241593, 161665899, -856104603, -500544946, 693410611, 395674299, -1015235909, 1115608337, 1187999872, -31006095, -219180466, -1676061637,
				3105	1040194153, -1339307841, -1527110163, -1884722688, -179148713, -431014627, -1789789823, -1209719926, 684519765, -486734513, 1734740619, -1971673751, -932421915, -2064668066, -937135958,
				3106	-790946468, -69070309, 1561601454, 26169001, -160734571, 1330043462, -486734512, -18796768, -470303314, 113421364, 1615760212, 1688217556, 1223719184, 536568131, 1682609873, 2935161,
				3107	-414769471, -1027490137, 1602276102, 1050490461 ]
				3108	} --></div></div>
				3109	<div class="section">
				3110	<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>
				3111	<div class="section">
				3112	<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>
				3113
				3114	<ul>
				3115
				3116	<li>
				3117	<p>Syntax:</p>
				3118
				3119	<div class="source">
				3120	<div class="source">
				3121	<pre>get-year/get-month/get-day/get-hour/get-minute/get-second/get-millisecond(temporal_expression)
				3122	</pre></div></div></li>
				3123
				3124	<li>
				3125	<p>Accessors for accessing fields in a temporal value</p></li>
				3126
				3127	<li>Arguments:
				3128
				3129	<ul>
				3130
				3131	<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>
				3132	</ul></li>
				3133
				3134	<li>Return Value:
				3135
				3136	<ul>
				3137
				3138	<li>An <tt>int64</tt> value representing the field to be extracted.</li>
				3139	</ul></li>
				3140
				3141	<li>
				3142	<p>Example:</p>
				3143
				3144	<div class="source">
				3145	<div class="source">
				3146	<pre>let $c1 := date("2010-10-30")
				3147	let $c2 := datetime("1987-11-19T23:49:23.938")
				3148	let $c3 := time("12:23:34.930+07:00")
				3149	let $c4 := duration("P3Y73M632DT49H743M3948.94S")
				3150
				3151	return {"year": get-year($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)}
				3152	</pre></div></div></li>
				3153	</ul>
				3154
				3155	<ul>
				3156
				3157	<li>
				3158	<p>The expected result is:</p>
				3159
				3160	<div class="source">
				3161	<div class="source">
				3162	<pre>{ "year": 2010, "month": 11, "day": 30, "hour": 5, "min": 28, "second": 23, "ms": 94 }
				3163	</pre></div></div></li>
				3164	</ul></div>
				3165	<div class="section">
				3166	<h3><a name="adjust-datetime-for-timezone"></a>adjust-datetime-for-timezone</h3>
				3167
				3168	<ul>
				3169
				3170	<li>
				3171	<p>Syntax:</p>
				3172
				3173	<div class="source">
				3174	<div class="source">
				3175	<pre>adjust-datetime-for-timezone(datetime_expression, string_expression)
				3176	</pre></div></div></li>
				3177
				3178	<li>
				3179	<p>Adjusts the given datetime <tt>datetime_expression</tt> by applying the timezone information <tt>string_expression</tt>.</p></li>
				3180
				3181	<li>Arguments:
				3182
				3183	<ul>
				3184
				3185	<li><tt>datetime_expression</tt> : A <tt>datetime</tt> value to be adjusted.</li>
				3186
				3187	<li><tt>string_expression</tt> : A <tt>string</tt> representing the timezone information.</li>
				3188	</ul></li>
				3189
				3190	<li>Return Value:
				3191
				3192	<ul>
				3193
				3194	<li>A <tt>string</tt> value representing the new datetime after being adjusted by the timezone information.</li>
				3195	</ul></li>
				3196
				3197	<li>
				3198	<p>Example:</p>
				3199
				3200	<div class="source">
				3201	<div class="source">
				3202	<pre>use dataverse TinySocial;
				3203
				3204	for $i in dataset('TweetMessages')
				3205	return {"adjusted-send-time": adjust-datetime-for-timezone($i.send-time, "+08:00"), "message": $i.message-text}
				3206	</pre></div></div></li>
				3207	</ul>
				3208
				3209	<ul>
				3210
				3211	<li>
				3212	<p>The expected result is:</p>
				3213
				3214	<div class="source">
				3215	<div class="source">
				3216	<pre>{ "adjusted-send-time": "2008-04-26T18:10:00.000+08:00", "message": " love t-mobile its customization is good:)" }
				3217	{ "adjusted-send-time": "2010-05-13T18:10:00.000+08:00", "message": " like verizon its shortcut-menu is awesome:)" }
				3218	{ "adjusted-send-time": "2006-11-04T18:10:00.000+08:00", "message": " like motorola the speed is good:)" }
				3219	{ "adjusted-send-time": "2011-12-26T18:10:00.000+08:00", "message": " like sprint the voice-command is mind-blowing:)" }
				3220	{ "adjusted-send-time": "2006-08-04T18:10:00.000+08:00", "message": " can't stand motorola its speed is terrible:(" }
				3221	{ "adjusted-send-time": "2010-05-07T18:10:00.000+08:00", "message": " like iphone the voice-clarity is good:)" }
				3222	{ "adjusted-send-time": "2011-08-25T18:10:00.000+08:00", "message": " like samsung the platform is good" }
				3223	{ "adjusted-send-time": "2005-10-14T18:10:00.000+08:00", "message": " like t-mobile the shortcut-menu is awesome:)" }
				3224	{ "adjusted-send-time": "2012-07-21T18:10:00.000+08:00", "message": " love verizon its voicemail-service is awesome" }
				3225	{ "adjusted-send-time": "2008-01-26T18:10:00.000+08:00", "message": " hate verizon its voice-clarity is OMG:(" }
				3226	{ "adjusted-send-time": "2008-03-09T18:10:00.000+08:00", "message": " can't stand iphone its platform is terrible" }
				3227	{ "adjusted-send-time": "2010-02-13T18:10:00.000+08:00", "message": " like samsung the voice-command is amazing:)" }
				3228	</pre></div></div></li>
				3229	</ul></div>
				3230	<div class="section">
				3231	<h3><a name="adjust-time-for-timezone"></a>adjust-time-for-timezone</h3>
				3232
				3233	<ul>
				3234
				3235	<li>
				3236	<p>Syntax:</p>
				3237
				3238	<div class="source">
				3239	<div class="source">
				3240	<pre>adjust-time-for-timezone(time_expression, string_expression)
				3241	</pre></div></div></li>
				3242
				3243	<li>
				3244	<p>Adjusts the given time <tt>time_expression</tt> by applying the timezone information <tt>string_expression</tt>.</p></li>
				3245
				3246	<li>Arguments:
				3247
				3248	<ul>
				3249
				3250	<li><tt>time_expression</tt> : A <tt>time</tt> value to be adjusted.</li>
				3251
				3252	<li><tt>string_expression</tt> : A <tt>string</tt> representing the timezone information.</li>
				3253	</ul></li>
				3254
				3255	<li>Return Value:
				3256
				3257	<ul>
				3258
				3259	<li>A <tt>string</tt> value representing the new time after being adjusted by the timezone information.</li>
				3260	</ul></li>
				3261
				3262	<li>
				3263	<p>Example:</p>
				3264
				3265	<div class="source">
				3266	<div class="source">
				3267	<pre>use dataverse TinySocial;
				3268
				3269	for $i in dataset('TweetMessages')
				3270	return {"adjusted-send-time": adjust-time-for-timezone(time-from-datetime($i.send-time), "+08:00"), "message": $i.message-text}
				3271	</pre></div></div></li>
				3272	</ul>
				3273
				3274	<ul>
				3275
				3276	<li>
				3277	<p>The expected result is:</p>
				3278
				3279	<div class="source">
				3280	<div class="source">
				3281	<pre>{ "adjusted-send-time": "18:10:00.000+08:00", "message": " love t-mobile its customization is good:)" }
				3282	{ "adjusted-send-time": "18:10:00.000+08:00", "message": " like verizon its shortcut-menu is awesome:)" }
				3283	{ "adjusted-send-time": "18:10:00.000+08:00", "message": " like motorola the speed is good:)" }
				3284	{ "adjusted-send-time": "18:10:00.000+08:00", "message": " like sprint the voice-command is mind-blowing:)" }
				3285	{ "adjusted-send-time": "18:10:00.000+08:00", "message": " can't stand motorola its speed is terrible:(" }
				3286	{ "adjusted-send-time": "18:10:00.000+08:00", "message": " like iphone the voice-clarity is good:)" }
				3287	{ "adjusted-send-time": "18:10:00.000+08:00", "message": " like samsung the platform is good" }
				3288	{ "adjusted-send-time": "18:10:00.000+08:00", "message": " like t-mobile the shortcut-menu is awesome:)" }
				3289	{ "adjusted-send-time": "18:10:00.000+08:00", "message": " love verizon its voicemail-service is awesome" }
				3290	{ "adjusted-send-time": "18:10:00.000+08:00", "message": " hate verizon its voice-clarity is OMG:(" }
				3291	{ "adjusted-send-time": "18:10:00.000+08:00", "message": " can't stand iphone its platform is terrible" }
				3292	{ "adjusted-send-time": "18:10:00.000+08:00", "message": " like samsung the voice-command is amazing:)" }
				3293	</pre></div></div></li>
				3294	</ul></div>
				3295	<div class="section">
				3296	<h3><a name="calendar-duration-from-datetime"></a>calendar-duration-from-datetime</h3>
				3297
				3298	<ul>
				3299
				3300	<li>
				3301	<p>Syntax:</p>
				3302
				3303	<div class="source">
				3304	<div class="source">
				3305	<pre>calendar-duration-from-datetime(datetime_expression, duration_expression)
				3306	</pre></div></div></li>
				3307
				3308	<li>
				3309	<p>Gets a user-friendly representation of the duration <tt>duration_expression</tt> based on the given datetime <tt>datetime_expression</tt>.</p></li>
				3310
				3311	<li>Arguments:
				3312
				3313	<ul>
				3314
				3315	<li><tt>datetime_expression</tt> : A <tt>datetime</tt> value to be used as the reference time point.</li>
				3316
				3317	<li><tt>duration_expression</tt> : A <tt>duration</tt> value to be converted.</li>
				3318	</ul></li>
				3319
				3320	<li>Return Value:
				3321
				3322	<ul>
				3323
				3324	<li>A <tt>duration</tt> value with the duration as <tt>duration_expression</tt> but with a user-friendly representation.</li>
				3325	</ul></li>
				3326
				3327	<li>
				3328	<p>Example:</p>
				3329
				3330	<div class="source">
				3331	<div class="source">
				3332	<pre>use dataverse TinySocial;
				3333
				3334	for $i in dataset('TweetMessages')
				3335	where $i.send-time > datetime("2011-01-01T00:00:00")
				3336	return {"since-2011": subtract-datetime($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")))}
				3337	</pre></div></div></li>
				3338	</ul>
				3339
				3340	<ul>
				3341
				3342	<li>
				3343	<p>The expected result is:</p>
				3344
				3345	<div class="source">
				3346	<div class="source">
				3347	<pre>{ "since-2011": duration("P359DT10H10M"), "since-2011-user-friendly": duration("P11M23DT10H10M") }
				3348	{ "since-2011": duration("P236DT10H10M"), "since-2011-user-friendly": duration("P7M23DT10H10M") }
				3349	{ "since-2011": duration("P567DT10H10M"), "since-2011-user-friendly": duration("P1Y6M18DT10H10M") }
				3350	</pre></div></div></li>
				3351	</ul></div>
				3352	<div class="section">
				3353	<h3><a name="get-year-month-durationget-day-time-duration"></a>get-year-month-duration/get-day-time-duration</h3>
				3354
				3355	<ul>
				3356
				3357	<li>
				3358	<p>Syntax:</p>
				3359
				3360	<div class="source">
				3361	<div class="source">
				3362	<pre>get-year-month-duration/get-day-time-duration(duration_expression)
				3363	</pre></div></div></li>
				3364
				3365	<li>
				3366	<p>Extracts the correct <tt>duration</tt> subtype from <tt>duration_expression</tt>.</p></li>
				3367
				3368	<li>Arguments:
				3369
				3370	<ul>
				3371
				3372	<li><tt>duration_expression</tt> : A <tt>duration</tt> value to be converted.</li>
				3373	</ul></li>
				3374
				3375	<li>Return Value:
				3376
				3377	<ul>
				3378
				3379	<li>A <tt>year-month-duration</tt> value or a <tt>day-time-duration</tt> value.</li>
				3380	</ul></li>
				3381
				3382	<li>
				3383	<p>Example:</p>
				3384
				3385	<div class="source">
				3386	<div class="source">
				3387	<pre>let $i := get-year-month-duration(duration("P12M50DT10H"))
				3388	return $i;
				3389	</pre></div></div></li>
				3390	</ul>
				3391
				3392	<ul>
				3393
				3394	<li>
				3395	<p>The expected result is:</p>
				3396
				3397	<div class="source">
				3398	<div class="source">
				3399	<pre>year-month-duration("P1Y")
				3400	</pre></div></div></li>
				3401	</ul></div>
				3402	<div class="section">
				3403	<h3><a name="months-from-year-month-durationmilliseconds-from-day-time-duration"></a>months-from-year-month-duration/milliseconds-from-day-time-duration</h3>
				3404
				3405	<ul>
				3406
				3407	<li>
				3408	<p>Syntax:</p>
				3409
				3410	<div class="source">
				3411	<div class="source">
				3412	<pre>months-from-year-month-duration/milliseconds-from-day-time-duration(duration_expression)
				3413	</pre></div></div></li>
				3414
				3415	<li>
				3416	<p>Extracts the number of months or the number of milliseconds from the <tt>duration</tt> subtype.</p></li>
				3417
				3418	<li>Arguments:
				3419
				3420	<ul>
				3421
				3422	<li><tt>duration_expression</tt> : A <tt>duration</tt> of the correct subtype.</li>
				3423	</ul></li>
				3424
				3425	<li>Return Value:
				3426
				3427	<ul>
				3428
				3429	<li>An <tt>int64</tt> representing the number or months/milliseconds.</li>
				3430	</ul></li>
				3431
				3432	<li>
				3433	<p>Example:</p>
				3434
				3435	<div class="source">
				3436	<div class="source">
				3437	<pre>let $i := months-from-year-month-duration(get-year-month-duration(duration("P5Y7MT50M")))
				3438	return $i;
				3439	</pre></div></div></li>
				3440	</ul>
				3441
				3442	<ul>
				3443
				3444	<li>
				3445	<p>The expected result is:</p>
				3446
				3447	<div class="source">
				3448	<div class="source">
				3449	<pre>67
				3450	</pre></div></div></li>
				3451	</ul></div>
				3452	<div class="section">
				3453	<h3><a name="duration-from-monthsduration-from-ms"></a>duration-from-months/duration-from-ms</h3>
				3454
				3455	<ul>
				3456
				3457	<li>
				3458	<p>Syntax:</p>
				3459
				3460	<div class="source">
				3461	<div class="source">
				3462	<pre>duration-from-months/duration-from-ms(number_expression)
				3463	</pre></div></div></li>
				3464
				3465	<li>
				3466	<p>Creates a <tt>duration</tt> from <tt>number_expression</tt>.</p></li>
				3467
				3468	<li>Arguments:
				3469
				3470	<ul>
				3471
				3472	<li><tt>number_expression</tt> : An <tt>int64</tt> representing the number of months/milliseconds</li>
				3473	</ul></li>
				3474
				3475	<li>Return Value:
				3476
				3477	<ul>
				3478
				3479	<li>A <tt>duration</tt> containing <tt>number_expression</tt> value for months/milliseconds</li>
				3480	</ul></li>
				3481
				3482	<li>
				3483	<p>Example:</p>
				3484
				3485	<div class="source">
				3486	<div class="source">
				3487	<pre>let $i := duration-from-months(8)
				3488	return $i;
				3489	</pre></div></div></li>
				3490
				3491	<li>
				3492	<p>The expected result is:</p>
				3493
				3494	<div class="source">
				3495	<div class="source">
				3496	<pre>duration("P8M")
				3497	</pre></div></div></li>
				3498	</ul></div>
				3499	<div class="section">
				3500	<h3><a name="duration-from-interval"></a>duration-from-interval</h3>
				3501
				3502	<ul>
				3503
				3504	<li>
				3505	<p>Syntax:</p>
				3506
				3507	<div class="source">
				3508	<div class="source">
				3509	<pre>duration-from-interval(interval_expression)
				3510	</pre></div></div></li>
				3511
				3512	<li>
				3513	<p>Creates a <tt>duration</tt> from <tt>interval_expression</tt>.</p></li>
				3514
				3515	<li>Arguments:
				3516
				3517	<ul>
				3518
				3519	<li><tt>interval_expression</tt> : An <tt>interval</tt> value</li>
				3520	</ul></li>
				3521
				3522	<li>Return Value:
				3523
				3524	<ul>
				3525
				3526	<li>A <tt>duration</tt> repesenting the time in the <tt>interval_expression</tt></li>
				3527	</ul></li>
				3528
				3529	<li>
				3530	<p>Example:</p>
				3531
				3532	<div class="source">
				3533	<div class="source">
				3534	<pre>let $itv1 := interval-from-date("2010-10-30", "2010-12-21")
				3535	let $itv2 := interval-from-datetime("2012-06-26T01:01:01.111", "2012-07-27T02:02:02.222")
				3536	let $itv3 := interval-from-time("12:32:38", "20:29:20")
				3537
				3538	return { "dr1" : duration-from-interval($itv1),
				3539	"dr2" : duration-from-interval($itv2),
				3540	"dr3" : duration-from-interval($itv3),
				3541	"dr4" : duration-from-interval(null) }
				3542	</pre></div></div></li>
				3543
				3544	<li>
				3545	<p>The expected result is:</p>
				3546
				3547	<div class="source">
				3548	<div class="source">
				3549	<pre>{ "dr1": day-time-duration("P52D"),
				3550	"dr2": day-time-duration("P31DT1H1M1.111S"),
				3551	"dr3": day-time-duration("PT7H56M42S"),
				3552	"dr4": null }
				3553	</pre></div></div></li>
				3554	</ul></div>
				3555	<div class="section">
				3556	<h3><a name="current-date"></a>current-date</h3>
				3557
				3558	<ul>
				3559
				3560	<li>
				3561	<p>Syntax:</p>
				3562
				3563	<div class="source">
				3564	<div class="source">
				3565	<pre>current-date()
				3566	</pre></div></div></li>
				3567
				3568	<li>
				3569	<p>Gets the current date.</p></li>
				3570
				3571	<li>Arguments: None</li>
				3572
				3573	<li>Return Value:
				3574
				3575	<ul>
				3576
				3577	<li>A <tt>date</tt> value of the date when the function is called.</li>
				3578	</ul></li>
				3579	</ul></div>
				3580	<div class="section">
				3581	<h3><a name="current-time"></a>current-time</h3>
				3582
				3583	<ul>
				3584
				3585	<li>
				3586	<p>Syntax:</p>
				3587
				3588	<div class="source">
				3589	<div class="source">
				3590	<pre>current-time()
				3591	</pre></div></div></li>
				3592
				3593	<li>
				3594	<p>Get the current time</p></li>
				3595
				3596	<li>Arguments: None</li>
				3597
				3598	<li>Return Value:
				3599
				3600	<ul>
				3601
				3602	<li>A <tt>time</tt> value of the time when the function is called.</li>
				3603	</ul></li>
				3604	</ul></div>
				3605	<div class="section">
				3606	<h3><a name="current-datetime"></a>current-datetime</h3>
				3607
				3608	<ul>
				3609
				3610	<li>
				3611	<p>Syntax:</p>
				3612
				3613	<div class="source">
				3614	<div class="source">
				3615	<pre>current-datetime()
				3616	</pre></div></div></li>
				3617
				3618	<li>
				3619	<p>Get the current datetime</p></li>
				3620
				3621	<li>Arguments: None</li>
				3622
				3623	<li>Return Value:
				3624
				3625	<ul>
				3626
				3627	<li>A <tt>datetime</tt> value of the datetime when the function is called.</li>
				3628	</ul></li>
				3629
				3630	<li>
				3631	<p>Example:</p>
				3632
				3633	<div class="source">
				3634	<div class="source">
				3635	<pre>{"current-date": current-date(),
				3636	"current-time": current-time(),
				3637	"current-datetime": current-datetime()}
				3638	</pre></div></div></li>
				3639	</ul>
				3640
				3641	<ul>
				3642
				3643	<li>
				3644	<p>The expected result is:</p>
				3645
				3646	<div class="source">
				3647	<div class="source">
				3648	<pre>{ "current-date": date("2013-04-06"),
				3649	"current-time": time("00:48:44.093Z"),
				3650	"current-datetime": datetime("2013-04-06T00:48:44.093Z") }
				3651	</pre></div></div></li>
				3652	</ul></div>
				3653	<div class="section">
				3654	<h3><a name="get-date-from-datetime"></a>get-date-from-datetime</h3>
				3655
				3656	<ul>
				3657
				3658	<li>
				3659	<p>Syntax:</p>
				3660
				3661	<div class="source">
				3662	<div class="source">
				3663	<pre>get-date-from-datetime(datetime_expression)
				3664	</pre></div></div></li>
				3665
				3666	<li>
				3667	<p>Gets the date value from the given datetime value <tt>datetime_expression</tt>.</p></li>
				3668
				3669	<li>Arguments:
				3670
				3671	<ul>
				3672
				3673	<li><tt>datetime_expression</tt>: A <tt>datetime</tt> value to be extracted from.</li>
				3674	</ul></li>
				3675
				3676	<li>Return Value:
				3677
				3678	<ul>
				3679
				3680	<li>A <tt>date</tt> value from the datetime.</li>
				3681	</ul></li>
				3682	</ul></div>
				3683	<div class="section">
				3684	<h3><a name="get-time-from-datetime"></a>get-time-from-datetime</h3>
				3685
				3686	<ul>
				3687
				3688	<li>
				3689	<p>Syntax:</p>
				3690
				3691	<div class="source">
				3692	<div class="source">
				3693	<pre>get-time-from-datetime(datetime_expression)
				3694	</pre></div></div></li>
				3695
				3696	<li>
				3697	<p>Get the time value from the given datetime value <tt>datetime_expression</tt></p></li>
				3698
				3699	<li>Arguments:
				3700
				3701	<ul>
				3702
				3703	<li><tt>datetime_expression</tt>: A <tt>datetime</tt> value to be extracted from</li>
				3704	</ul></li>
				3705
				3706	<li>Return Value:
				3707
				3708	<ul>
				3709
				3710	<li>A <tt>time</tt> value from the datetime.</li>
				3711	</ul></li>
				3712
				3713	<li>
				3714	<p>Example:</p>
				3715
				3716	<div class="source">
				3717	<div class="source">
				3718	<pre>use dataverse TinySocial;
				3719
				3720	for $i in dataset('TweetMessages')
				3721	where $i.send-time > datetime("2011-01-01T00:00:00")
				3722	return {"send-date": get-date-from-datetime($i.send-time), "send-time": get-time-from-datetime($i.send-time)}
				3723	</pre></div></div></li>
				3724	</ul>
				3725
				3726	<ul>
				3727
				3728	<li>
				3729	<p>The expected result is:</p>
				3730
				3731	<div class="source">
				3732	<div class="source">
				3733	<pre>{ "send-date": date("2011-12-26"), "send-time": time("10:10:00.000Z") }
				3734	{ "send-date": date("2011-08-25"), "send-time": time("10:10:00.000Z") }
				3735	{ "send-date": date("2012-07-21"), "send-time": time("10:10:00.000Z") }
				3736	</pre></div></div></li>
				3737	</ul></div>
				3738	<div class="section">
				3739	<h3><a name="day-of-week"></a>day-of-week</h3>
				3740
				3741	<ul>
				3742
				3743	<li>
				3744	<p>Syntax:</p>
				3745
				3746	<div class="source">
				3747	<div class="source">
				3748	<pre>day-of-week(date_expression)
				3749	</pre></div></div></li>
				3750
				3751	<li>
				3752	<p>Finds the day of the week for a given date (1-7)</p></li>
				3753
				3754	<li>Arguments:
				3755
				3756	<ul>
				3757
				3758	<li><tt>date_expression</tt>: A <tt>date</tt> value (Can also be a <tt>datetime</tt>)</li>
				3759	</ul></li>
				3760
				3761	<li>Return Value:
				3762
				3763	<ul>
				3764
				3765	<li>An <tt>int8</tt> representing the day of the week (1-7)</li>
				3766	</ul></li>
				3767
				3768	<li>
				3769	<p>Example:</p>
				3770
				3771	<div class="source">
				3772	<div class="source">
				3773	<pre>let $i := day-of-week( datetime("2012-12-30T12:12:12.039Z"))
				3774	return $i;
				3775	</pre></div></div></li>
				3776	</ul>
				3777
				3778	<ul>
				3779
				3780	<li>
				3781	<p>The expected result is:</p>
				3782
				3783	<div class="source">
				3784	<div class="source">
				3785	<pre>7
				3786	</pre></div></div></li>
				3787	</ul></div>
				3788	<div class="section">
				3789	<h3><a name="date-from-unix-time-in-days"></a>date-from-unix-time-in-days</h3>
				3790
				3791	<ul>
				3792
				3793	<li>
				3794	<p>Syntax:</p>
				3795
				3796	<div class="source">
				3797	<div class="source">
				3798	<pre>date-from-unix-time-in-days(numeric_expression)
				3799	</pre></div></div></li>
				3800
				3801	<li>
				3802	<p>Gets a date representing the time after <tt>numeric_expression</tt> days since 1970-01-01.</p></li>
				3803
				3804	<li>Arguments:
				3805
				3806	<ul>
				3807
				3808	<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>
				3809	</ul></li>
				3810
				3811	<li>Return Value:
				3812
				3813	<ul>
				3814
				3815	<li>A <tt>date</tt> value as the time after <tt>numeric_expression</tt> days since 1970-01-01.</li>
				3816	</ul></li>
				3817	</ul></div>
				3818	<div class="section">
				3819	<h3><a name="datetime-from-unix-time-in-ms"></a>datetime-from-unix-time-in-ms</h3>
				3820
				3821	<ul>
				3822
				3823	<li>
				3824	<p>Syntax:</p>
				3825
				3826	<div class="source">
				3827	<div class="source">
				3828	<pre>datetime-from-unix-time-in-ms(numeric_expression)
				3829	</pre></div></div></li>
				3830
				3831	<li>
				3832	<p>Gets a datetime representing the time after <tt>numeric_expression</tt> milliseconds since 1970-01-01T00:00:00Z.</p></li>
				3833
				3834	<li>Arguments:
				3835
				3836	<ul>
				3837
				3838	<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>
				3839	</ul></li>
				3840
				3841	<li>Return Value:
				3842
				3843	<ul>
				3844
				3845	<li>A <tt>datetime</tt> value as the time after <tt>numeric_expression</tt> milliseconds since 1970-01-01T00:00:00Z.</li>
				3846	</ul></li>
				3847	</ul></div>
				3848	<div class="section">
				3849	<h3><a name="datetime-from-unix-time-in-secs"></a>datetime-from-unix-time-in-secs</h3>
				3850
				3851	<ul>
				3852
				3853	<li>
				3854	<p>Syntax:</p>
				3855
				3856	<div class="source">
				3857	<div class="source">
				3858	<pre>datetime-from-unix-time-in-secs(numeric_expression)
				3859	</pre></div></div></li>
				3860
				3861	<li>
				3862	<p>Gets a datetime representing the time after <tt>numeric_expression</tt> seconds since 1970-01-01T00:00:00Z.</p></li>
				3863
				3864	<li>Arguments:
				3865
				3866	<ul>
				3867
				3868	<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>
				3869	</ul></li>
				3870
				3871	<li>Return Value:
				3872
				3873	<ul>
				3874
				3875	<li>A <tt>datetime</tt> value as the time after <tt>numeric_expression</tt> seconds since 1970-01-01T00:00:00Z.</li>
				3876	</ul></li>
				3877	</ul></div>
				3878	<div class="section">
				3879	<h3><a name="datetime-from-date-time"></a>datetime-from-date-time</h3>
				3880
				3881	<ul>
				3882
				3883	<li>Syntax:</li>
				3884	</ul>
				3885	<p>datetime-from-date-time(date_expression,time_expression)</p>
				3886
				3887	<ul>
				3888
				3889	<li>Gets a datetime representing the combination of <tt>date_expression</tt> and <tt>time_expression</tt>
				3890
				3891	<ul>
				3892
				3893	<li>Arguments:</li>
				3894
				3895	<li><tt>date_expression</tt>: A <tt>date</tt> value</li>
				3896
				3897	<li><tt>time_expression</tt> A <tt>time</tt> value</li>
				3898	</ul></li>
				3899
				3900	<li>Return Value:
				3901
				3902	<ul>
				3903
				3904	<li>A <tt>datetime</tt> value by combining <tt>date_expression</tt> and <tt>time_expression</tt></li>
				3905	</ul></li>
				3906	</ul></div>
				3907	<div class="section">
				3908	<h3><a name="time-from-unix-time-in-ms"></a>time-from-unix-time-in-ms</h3>
				3909
				3910	<ul>
				3911
				3912	<li>
				3913	<p>Syntax:</p>
				3914
				3915	<div class="source">
				3916	<div class="source">
				3917	<pre>time-from-unix-time-in-ms(numeric_expression)
				3918	</pre></div></div></li>
				3919
				3920	<li>
				3921	<p>Gets a time representing the time after <tt>numeric_expression</tt> milliseconds since 00:00:00.000Z.</p></li>
				3922
				3923	<li>Arguments:
				3924
				3925	<ul>
				3926
				3927	<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>
				3928	</ul></li>
				3929
				3930	<li>Return Value:
				3931
				3932	<ul>
				3933
				3934	<li>A <tt>time</tt> value as the time after <tt>numeric_expression</tt> milliseconds since 00:00:00.000Z.</li>
				3935	</ul></li>
				3936
				3937	<li>
				3938	<p>Example:</p>
				3939
				3940	<div class="source">
				3941	<div class="source">
				3942	<pre>use dataverse TinySocial;
				3943
				3944	let $d := date-from-unix-time-in-days(15800)
				3945	let $dt := datetime-from-unix-time-in-ms(1365139700000)
				3946	let $t := time-from-unix-time-in-ms(3748)
				3947	return {"date": $d, "datetime": $dt, "time": $t}
				3948	</pre></div></div></li>
				3949	</ul>
				3950
				3951	<ul>
				3952
				3953	<li>
				3954	<p>The expected result is:</p>
				3955
				3956	<div class="source">
				3957	<div class="source">
				3958	<pre>{ "date": date("2013-04-05"), "datetime": datetime("2013-04-05T05:28:20.000Z"), "time": time("00:00:03.748Z") }
				3959	</pre></div></div></li>
				3960	</ul></div>
				3961	<div class="section">
				3962	<h3><a name="parse-dateparse-timeparse-datetime"></a>parse-date/parse-time/parse-datetime</h3>
				3963
				3964	<ul>
				3965
				3966	<li>Syntax:</li>
				3967	</ul>
				3968	<p>parse-date/parse-time/parse-datetime(date_expression,formatting_expression)</p>
				3969
				3970	<ul>
				3971
				3972	<li>Creates a <tt>date/time/date-time</tt> value by treating <tt>date_expression</tt> with formatting <tt>formatting_expression</tt></li>
				3973
				3974	<li>Arguments:
				3975
				3976	<ul>
				3977
				3978	<li><tt>date_expression</tt>: A <tt>string</tt> value representing the <tt>date/time/datetime</tt>.</li>
				3979
				3980	<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>
				3981
				3982	<li><tt>h</tt> hours</li>
				3983
				3984	<li><tt>m</tt> minutes</li>
				3985
				3986	<li><tt>s</tt> seconds</li>
				3987
				3988	<li><tt>n</tt> milliseconds</li>
				3989
				3990	<li><tt>a</tt> am/pm</li>
				3991
				3992	<li><tt>z</tt> timezone</li>
				3993
				3994	<li><tt>Y</tt> year</li>
				3995
				3996	<li><tt>M</tt> month</li>
				3997
				3998	<li><tt>D</tt> day</li>
				3999
				4000	<li><tt>W</tt> weekday</li>
				4001
				4002	<li><tt>-</tt>, <tt>'</tt>, <tt>/</tt>, <tt>.</tt>, <tt>,</tt>, <tt>T</tt> seperators for both time and date</li>
				4003	</ul></li>
				4004
				4005	<li>Return Value:
				4006
				4007	<ul>
				4008
				4009	<li>A <tt>date/time/date-time</tt> value corresponding to <tt>date_expression</tt></li>
				4010	</ul></li>
				4011
				4012	<li>
				4013	<p>Example:</p>
				4014
				4015	<div class="source">
				4016	<div class="source">
				4017	<pre>let $i := parse-time("30:30","m:s")
				4018	return $i;
				4019	</pre></div></div></li>
				4020
				4021	<li>
				4022	<p>The expected result is:</p>
				4023
				4024	<div class="source">
				4025	<div class="source">
				4026	<pre>time("00:30:30.000Z")
				4027	</pre></div></div></li>
				4028	</ul></div>
				4029	<div class="section">
				4030	<h3><a name="print-dateprint-timeprint-datetime"></a>print-date/print-time/print-datetime</h3>
				4031
				4032	<ul>
				4033
				4034	<li>Syntax:</li>
				4035	</ul>
				4036	<p>print-date/print-time/print-datetime(date_expression,formatting_expression)</p>
				4037
				4038	<ul>
				4039
				4040	<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>
				4041
				4042	<li>Arguments:
				4043
				4044	<ul>
				4045
				4046	<li><tt>date_expression</tt>: A <tt>date/time/datetime</tt> value.</li>
				4047
				4048	<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>
				4049
				4050	<li><tt>h</tt> hours</li>
				4051
				4052	<li><tt>m</tt> minutes</li>
				4053
				4054	<li><tt>s</tt> seconds</li>
				4055
				4056	<li><tt>n</tt> milliseconds</li>
				4057
				4058	<li><tt>a</tt> am/pm</li>
				4059
				4060	<li><tt>z</tt> timezone</li>
				4061
				4062	<li><tt>Y</tt> year</li>
				4063
				4064	<li><tt>M</tt> month</li>
				4065
				4066	<li><tt>D</tt> day</li>
				4067
				4068	<li><tt>W</tt> weekday</li>
				4069
				4070	<li><tt>-</tt>, <tt>'</tt>, <tt>/</tt>, <tt>.</tt>, <tt>,</tt>, <tt>T</tt> seperators for both time and date</li>
				4071	</ul></li>
				4072
				4073	<li>Return Value:
				4074
				4075	<ul>
				4076
				4077	<li>A <tt>string</tt> value corresponding to <tt>date_expression</tt></li>
				4078	</ul></li>
				4079
				4080	<li>
				4081	<p>Example:</p>
				4082
				4083	<div class="source">
				4084	<div class="source">
				4085	<pre>let $i := print-time(time("00:30:30.000Z"),"m:s")
				4086	return $i;
				4087	</pre></div></div></li>
				4088
				4089	<li>
				4090	<p>The expected result is:</p>
				4091
				4092	<div class="source">
				4093	<div class="source">
				4094	<pre>"30:30"
				4095	</pre></div></div></li>
				4096	</ul></div>
				4097	<div class="section">
				4098	<h3><a name="get-interval-start_get-interval-end"></a>get-interval-start, get-interval-end</h3>
				4099
				4100	<ul>
				4101
				4102	<li>
				4103	<p>Syntax:</p>
				4104
				4105	<div class="source">
				4106	<div class="source">
				4107	<pre>get-interval-start/get-interval-end(interval)
				4108	</pre></div></div></li>
				4109
				4110	<li>
				4111	<p>Gets the start/end of the given interval.</p></li>
				4112
				4113	<li>Arguments:
				4114
				4115	<ul>
				4116
				4117	<li><tt>interval</tt>: the interval to be accessed.</li>
				4118	</ul></li>
				4119
				4120	<li>Return Value:
				4121
				4122	<ul>
				4123
				4124	<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>
				4125	</ul></li>
				4126
				4127	<li>
				4128	<p>Example:</p>
				4129
				4130	<div class="source">
				4131	<div class="source">
				4132	<pre>let $itv := interval-start-from-date("1984-01-01", "P1Y")
				4133	return {"start": get-interval-start($itv), "end": get-interval-end($itv)}
				4134	</pre></div></div></li>
				4135	</ul>
				4136
				4137	<ul>
				4138
				4139	<li>
				4140	<p>The expected result is:</p>
				4141
				4142	<div class="source">
				4143	<div class="source">
				4144	<pre>{ "start": date("1984-01-01"), "end": date("1985-01-01") }
				4145	</pre></div></div></li>
				4146	</ul></div>
				4147	<div class="section">
				4148	<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>
				4149
				4150	<ul>
				4151
				4152	<li>
				4153	<p>Syntax:</p>
				4154
				4155	<div class="source">
				4156	<div class="source">
				4157	<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)
				4158	</pre></div></div></li>
				4159
				4160	<li>
				4161	<p>Gets the start/end of the given interval for the specific date/datetime/time type.</p></li>
				4162
				4163	<li>Arguments:
				4164
				4165	<ul>
				4166
				4167	<li><tt>interval</tt>: the interval to be accessed.</li>
				4168	</ul></li>
				4169
				4170	<li>Return Value:
				4171
				4172	<ul>
				4173
				4174	<li>A <tt>time</tt>, <tt>date</tt>, or <tt>datetime</tt> (depending on the function) representing the starting or ending time.</li>
				4175	</ul></li>
				4176
				4177	<li>
				4178	<p>Example:</p>
				4179
				4180	<div class="source">
				4181	<div class="source">
				4182	<pre>let $itv1 := interval-start-from-date("1984-01-01", "P1Y")
				4183	let $itv2 := interval-start-from-datetime("1984-01-01T08:30:00.000", "P1Y1H")
				4184	let $itv3 := interval-start-from-time("08:30:00.000", "P1H")
				4185	return {"start": get-interval-start-date($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)}
				4186	</pre></div></div></li>
				4187	</ul>
				4188
				4189	<ul>
				4190
				4191	<li>
				4192	<p>The expected result is:</p>
				4193
				4194	<div class="source">
				4195	<div class="source">
				4196	<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") }
				4197	</pre></div></div></li>
				4198	</ul></div>
				4199	<div class="section">
				4200	<h3><a name="get-overlapping-interval"></a>get-overlapping-interval</h3>
				4201
				4202	<ul>
				4203
				4204	<li>
				4205	<p>Syntax:</p>
				4206
				4207	<div class="source">
				4208	<div class="source">
				4209	<pre>get-overlapping-interval(interval_expression_1, interval_expression_2)
				4210	</pre></div></div></li>
				4211
				4212	<li>
				4213	<p>Gets the start/end of the given interval for the specific date/datetime/time type.</p></li>
				4214
				4215	<li>Arguments:
				4216
				4217	<ul>
				4218
				4219	<li><tt>interval_expression_1</tt>: an <tt>interval</tt> value</li>
				4220
				4221	<li><tt>interval_expression_2</tt>: an <tt>interval</tt> value</li>
				4222	</ul></li>
				4223
				4224	<li>Return Value:
				4225
				4226	<ul>
				4227
				4228	<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>
				4229	</ul></li>
				4230
				4231	<li>
				4232	<p>Example:</p>
				4233
				4234	<div class="source">
				4235	<div class="source">
				4236	<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"))),
				4237	"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"))),
				4238	"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"))),
				4239	"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"))),
				4240	"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"))),
				4241	"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"))) }
				4242	</pre></div></div></li>
				4243
				4244	<li>
				4245	<p>The expected result is:</p>
				4246
				4247	<div class="source">
				4248	<div class="source">
				4249	<pre>{ "overlap1": interval-time("12:23:39.000Z, 18:27:19.000Z"),
				4250	"overlap2": null,
				4251	"overlap3": null,
				4252	"overlap4": interval-date("2013-01-01, 2014-01-01"),
				4253	"overlap5": interval-datetime("1989-03-04T12:23:39.000Z, 2000-10-30T18:27:19.000Z"),
				4254	"overlap6": null }
				4255	</pre></div></div></li>
				4256	</ul></div>
				4257	<div class="section">
				4258	<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>
				4259	<p>See the <a href="allens.html">Allen’s Relations</a>.</p></div>
				4260	<div class="section">
				4261	<h3><a name="interval-bin"></a>interval-bin</h3>
				4262
				4263	<ul>
				4264
				4265	<li>
				4266	<p>Syntax:</p>
				4267
				4268	<div class="source">
				4269	<div class="source">
				4270	<pre>interval-bin(time-to-bin, time-bin-anchor, duration-bin-size)
				4271	</pre></div></div></li>
				4272
				4273	<li>
				4274	<p>Return the <tt>interval</tt> value representing the bin containing the <tt>time-to-bin</tt> value.</p></li>
				4275
				4276	<li>Arguments:
				4277
				4278	<ul>
				4279
				4280	<li><tt>time-to-bin</tt>: a date/time/datetime value representing the time to be binned.</li>
				4281
				4282	<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>
				4283
				4284	<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:
				4285
				4286	<ul>
				4287
				4288	<li>datetime +\|- year-month-duration</li>
				4289
				4290	<li>datetime +\|- day-time-duration</li>
				4291
				4292	<li>date +\|- year-month-duration</li>
				4293
				4294	<li>date +\|- day-time-duration</li>
				4295
				4296	<li>time +\|- day-time-duration</li>
				4297	</ul></li>
				4298	</ul></li>
				4299
				4300	<li>Return Value:
				4301
				4302	<ul>
				4303
				4304	<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>
				4305	</ul></li>
				4306
				4307	<li>
				4308	<p>Example:</p>
				4309
				4310	<div class="source">
				4311	<div class="source">
				4312	<pre>let $c1 := date("2010-10-30")
				4313	let $c2 := datetime("-1987-11-19T23:49:23.938")
				4314	let $c3 := time("12:23:34.930+07:00")
				4315
				4316	return { "bin1": interval-bin($c1, date("1990-01-01"), year-month-duration("P1Y")),
				4317	"bin2": interval-bin($c2, datetime("1990-01-01T00:00:00.000Z"), year-month-duration("P6M")),
				4318	"bin3": interval-bin($c3, time("00:00:00"), day-time-duration("PD1M")),
				4319	"bin4": interval-bin($c2, datetime("2013-01-01T00:00:00.000"), day-time-duration("PT24H"))
				4320	</pre></div></div> }</li>
				4321
				4322	<li>
				4323	<p>The expected result is:</p>
				4324
				4325	<div class="source">
				4326	<div class="source">
				4327	<pre>{ "bin1": interval-date("2010-01-01, 2011-01-01"),
				4328	"bin2": interval-datetime("-1987-07-01T00:00:00.000Z, -1986-01-01T00:00:00.000Z"),
				4329	"bin3": interval-time("05:23:00.000Z, 05:24:00.000Z"),
				4330	"bin4": interval-datetime("-1987-11-19T00:00:00.000Z, -1987-11-20T00:00:00.000Z")}
				4331	</pre></div></div></li>
				4332	</ul></div>
				4333	<div class="section">
				4334	<h3><a name="interval-from-date"></a>interval-from-date</h3>
				4335
				4336	<ul>
				4337
				4338	<li>
				4339	<p>Syntax:</p>
				4340
				4341	<div class="source">
				4342	<div class="source">
				4343	<pre>interval-from-date(string_expression1, string_expression2)
				4344	</pre></div></div></li>
				4345
				4346	<li>
				4347	<p>Constructor function for the <tt>interval</tt> type by parsing two date strings.</p></li>
				4348
				4349	<li>Arguments:
				4350
				4351	<ul>
				4352
				4353	<li><tt>string_expression1</tt> : The <tt>string</tt> value representing the starting date.</li>
				4354
				4355	<li><tt>string_expression2</tt> : The <tt>string</tt> value representing the ending date.</li>
				4356	</ul></li>
				4357
				4358	<li>Return Value:
				4359
				4360	<ul>
				4361
				4362	<li>An <tt>interval</tt> value between the two dates.</li>
				4363	</ul></li>
				4364
				4365	<li>
				4366	<p>Example:</p>
				4367
				4368	<div class="source">
				4369	<div class="source">
				4370	<pre>{"date-interval": interval-from-date("2012-01-01", "2013-04-01")}
				4371	</pre></div></div></li>
				4372	</ul>
				4373
				4374	<ul>
				4375
				4376	<li>
				4377	<p>The expected result is:</p>
				4378
				4379	<div class="source">
				4380	<div class="source">
				4381	<pre>{ "date-interval": interval-date("2012-01-01, 2013-04-01") }
				4382	</pre></div></div></li>
				4383	</ul></div>
				4384	<div class="section">
				4385	<h3><a name="interval-from-time"></a>interval-from-time</h3>
				4386
				4387	<ul>
				4388
				4389	<li>
				4390	<p>Syntax:</p>
				4391
				4392	<div class="source">
				4393	<div class="source">
				4394	<pre>interval-from-time(string_expression1, string_expression2)
				4395	</pre></div></div></li>
				4396
				4397	<li>
				4398	<p>Constructor function for the <tt>interval</tt> type by parsing two time strings.</p></li>
				4399
				4400	<li>Arguments:
				4401
				4402	<ul>
				4403
				4404	<li><tt>string_expression1</tt> : The <tt>string</tt> value representing the starting time.</li>
				4405
				4406	<li><tt>string_expression2</tt> : The <tt>string</tt> value representing the ending time.</li>
				4407	</ul></li>
				4408
				4409	<li>Return Value:
				4410
				4411	<ul>
				4412
				4413	<li>An <tt>interval</tt> value between the two times.</li>
				4414	</ul></li>
				4415
				4416	<li>
				4417	<p>Example:</p>
				4418
				4419	<div class="source">
				4420	<div class="source">
				4421	<pre>{"time-interval": interval-from-time("12:23:34.456Z", "233445567+0800")}
				4422	</pre></div></div></li>
				4423	</ul>
				4424
				4425	<ul>
				4426
				4427	<li>
				4428	<p>The expected result is:</p>
				4429
				4430	<div class="source">
				4431	<div class="source">
				4432	<pre>{ "time-interval": interval-time("12:23:34.456Z, 15:34:45.567Z") }
				4433	</pre></div></div></li>
				4434	</ul></div>
				4435	<div class="section">
				4436	<h3><a name="interval-from-datetime"></a>interval-from-datetime</h3>
				4437
				4438	<ul>
				4439
				4440	<li>
				4441	<p>Syntax:</p>
				4442
				4443	<div class="source">
				4444	<div class="source">
				4445	<pre>interval-from-datetime(string_expression1, string_expression2)
				4446	</pre></div></div></li>
				4447
				4448	<li>
				4449	<p>Constructor function for <tt>interval</tt> type by parsing two datetime strings.</p></li>
				4450
				4451	<li>Arguments:
				4452
				4453	<ul>
				4454
				4455	<li><tt>string_expression1</tt> : The <tt>string</tt> value representing the starting datetime.</li>
				4456
				4457	<li><tt>string_expression2</tt> : The <tt>string</tt> value representing the ending datetime.</li>
				4458	</ul></li>
				4459
				4460	<li>Return Value:
				4461
				4462	<ul>
				4463
				4464	<li>An <tt>interval</tt> value between the two datetimes.</li>
				4465	</ul></li>
				4466
				4467	<li>
				4468	<p>Example:</p>
				4469
				4470	<div class="source">
				4471	<div class="source">
				4472	<pre>{"datetime-interval": interval-from-datetime("2012-01-01T12:23:34.456+08:00", "20130401T153445567Z")}
				4473	</pre></div></div></li>
				4474	</ul>
				4475
				4476	<ul>
				4477
				4478	<li>
				4479	<p>The expected result is:</p>
				4480
				4481	<div class="source">
				4482	<div class="source">
				4483	<pre>{ "datetime-interval": interval-datetime("2012-01-01T04:23:34.456Z, 2013-04-01T15:34:45.567Z") }
				4484	</pre></div></div></li>
				4485	</ul></div>
				4486	<div class="section">
				4487	<h3><a name="interval-start-from-datetimedatetime"></a>interval-start-from-date/time/datetime</h3>
				4488
				4489	<ul>
				4490
				4491	<li>
				4492	<p>Syntax:</p>
				4493
				4494	<div class="source">
				4495	<div class="source">
				4496	<pre>interval-start-from-date/time/datetime(date/time/datetime, duration)
				4497	</pre></div></div></li>
				4498
				4499	<li>
				4500	<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>
				4501
				4502	<li>Arguments:
				4503
				4504	<ul>
				4505
				4506	<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>
				4507
				4508	<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>
				4509	</ul></li>
				4510
				4511	<li>Return Value:
				4512
				4513	<ul>
				4514
				4515	<li>An <tt>interval</tt> value representing the interval starting from the given time point with the length of duration.</li>
				4516	</ul></li>
				4517
				4518	<li>
				4519	<p>Example:</p>
				4520
				4521	<div class="source">
				4522	<div class="source">
				4523	<pre>let $itv1 := interval-start-from-date("1984-01-01", "P1Y")
				4524	let $itv2 := interval-start-from-time(time("02:23:28.394"), "PT3H24M")
				4525	let $itv3 := interval-start-from-datetime("1999-09-09T09:09:09.999", duration("P2M30D"))
				4526	return {"interval1": $itv1, "interval2": $itv2, "interval3": $itv3}
				4527	</pre></div></div></li>
				4528
				4529	<li>
				4530	<p>The expectecd result is:</p>
				4531
				4532	<div class="source">
				4533	<div class="source">
				4534	<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") }
				4535	</pre></div></div></li>
				4536	</ul></div>
				4537	<div class="section">
				4538	<h3><a name="overlap-bins"></a>overlap-bins</h3>
				4539
				4540	<ul>
				4541
				4542	<li>
				4543	<p>Return Value:</p>
				4544
				4545	<ul>
				4546
				4547	<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>
				4548	</ul></li>
				4549
				4550	<li>
				4551	<p>Syntax:</p>
				4552
				4553	<div class="source">
				4554	<div class="source">
				4555	<pre>overlap-bins(interval_expression, time-bin-anchor, duration-bin-size)
				4556	</pre></div></div></li>
				4557
				4558	<li>
				4559	<p>Returns an ordered list of <tt>interval</tt> values representing each bin that is overlapping the <tt>interval_expression</tt>.</p></li>
				4560
				4561	<li>Arguments:
				4562
				4563	<ul>
				4564
				4565	<li><tt>interval_expression</tt>: an <tt>interval</tt> value</li>
				4566
				4567	<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>
				4568
				4569	<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:
				4570
				4571	<ul>
				4572
				4573	<li>datetime +\|- year-month-duration</li>
				4574
				4575	<li>datetime +\|- day-time-duration</li>
				4576
				4577	<li>date +\|- year-month-duration</li>
				4578
				4579	<li>date +\|- day-time-duration</li>
				4580
				4581	<li>time +\|- day-time-duration</li>
				4582	</ul></li>
				4583	</ul></li>
				4584
				4585	<li>Return Value:
				4586
				4587	<ul>
				4588
				4589	<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>
				4590	</ul></li>
				4591
				4592	<li>
				4593	<p>Example:</p>
				4594
				4595	<div class="source">
				4596	<div class="source">
				4597	<pre>let $itv1 := interval-from-time(time("17:23:37"), time("18:30:21"))
				4598	let $itv2 := interval-from-date(date("1984-03-17"), date("2013-08-22"))
				4599	let $itv3 := interval-from-datetime(datetime("1800-01-01T23:59:48.938"), datetime("2015-07-26T13:28:30.218"))
				4600	return { "timebins": overlap-bins($itv1, time("00:00:00"), day-time-duration("PT30M")),
				4601	"datebins": overlap-bins($itv2, date("1990-01-01"), year-month-duration("P20Y")),
				4602	"datetimebins": overlap-bins($itv3, datetime("1900-01-01T00:00:00.000"), year-month-duration("P100Y")) }
				4603	</pre></div></div></li>
				4604
				4605	<li>
				4606	<p>The expected result is:</p>
				4607
				4608	<div class="source">
				4609	<div class="source">
				4610	<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") ],
				4611	"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") ],
				4612	"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") ] }
				4613	</pre></div></div></li>
				4614	</ul></div></div>
				4615	<div class="section">
				4616	<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>
				4617	<div class="section">
				4618	<h3><a name="get-record-fields"></a>get-record-fields</h3>
				4619
				4620	<ul>
				4621
				4622	<li>
				4623	<p>Syntax:</p>
				4624
				4625	<div class="source">
				4626	<div class="source">
				4627	<pre>get-record-fields(record_expression)
				4628	</pre></div></div></li>
				4629
				4630	<li>
				4631	<p>Access the record field names, type and open status for a given record.</p></li>
				4632
				4633	<li>Arguments:
				4634
				4635	<ul>
				4636
				4637	<li><tt>record_expression</tt> : a record value.</li>
				4638	</ul></li>
				4639
				4640	<li>Return Value:
				4641
				4642	<ul>
				4643
				4644	<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>
				4645	</ul></li>
				4646
				4647	<li>
				4648	<p>Example:</p>
				4649
				4650	<div class="source">
				4651	<div class="source">
				4652	<pre>let $r1 := {"id": 1,
				4653	"project": "AsterixDB",
				4654	"address": {"city": "Irvine", "state": "CA"},
				4655	"related": ["Hivestrix", "Preglix", "Apache VXQuery"] }
				4656	return get-record-fields($r1)
				4657	</pre></div></div></li>
				4658
				4659	<li>
				4660	<p>The expected result is:</p>
				4661
				4662	<div class="source">
				4663	<div class="source">
				4664	<pre>[ { "field-name": "id", "field-type": "INT64", "is-open": false },
				4665	{ "field-name": "project", "field-type": "STRING", "is-open": false },
				4666	{ "field-name": "address", "field-type": "RECORD", "is-open": false, "nested": [
				4667	{ "field-name": "city", "field-type": "STRING", "is-open": false },
				4668	{ "field-name": "state", "field-type": "STRING", "is-open": false } ] },
				4669	{ "field-name": "related", "field-type": "ORDEREDLIST", "is-open": false, "list": [
				4670	{ "field-type": "STRING" },
				4671	{ "field-type": "STRING" },
				4672	{ "field-type": "STRING" } ] } ]
				4673	</pre></div></div></li>
				4674	</ul>
				4675	<p>]</p></div>
				4676	<div class="section">
				4677	<h3><a name="get-record-field-value"></a>get-record-field-value</h3>
				4678
				4679	<ul>
				4680
				4681	<li>
				4682	<p>Syntax:</p>
				4683
				4684	<div class="source">
				4685	<div class="source">
				4686	<pre>get-record-field-value(record_expression, string_expression)
				4687	</pre></div></div></li>
				4688
				4689	<li>
				4690	<p>Access the field name given in the <tt>string_expression</tt> from the <tt>record_expression</tt>.</p></li>
				4691
				4692	<li>Arguments:
				4693
				4694	<ul>
				4695
				4696	<li><tt>record_expression</tt> : A <tt>record</tt> value.</li>
				4697
				4698	<li><tt>string_expression</tt> : A <tt>string</tt> representing the top level field name.</li>
				4699	</ul></li>
				4700
				4701	<li>Return Value:
				4702
				4703	<ul>
				4704
				4705	<li>An <tt>any</tt> value saved in the designated field of the record.</li>
				4706	</ul></li>
				4707
				4708	<li>
				4709	<p>Example:</p>
				4710
				4711	<div class="source">
				4712	<div class="source">
				4713	<pre>let $r1 := {"id": 1,
				4714	"project": "AsterixDB",
				4715	"address": {"city": "Irvine", "state": "CA"},
				4716	"related": ["Hivestrix", "Preglix", "Apache VXQuery"] }
				4717	return get-record-field-value($r1, "project")
				4718	</pre></div></div></li>
				4719
				4720	<li>
				4721	<p>The expected result is:</p>
				4722
				4723	<div class="source">
				4724	<div class="source">
				4725	<pre>"AsterixDB"
				4726	</pre></div></div></li>
				4727	</ul></div></div>
				4728	<div class="section">
				4729	<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>
				4730	<div class="section">
				4731	<h3><a name="create-uuid"></a>create-uuid</h3>
				4732
				4733	<ul>
				4734
				4735	<li>
				4736	<p>Syntax:</p>
				4737
				4738	<div class="source">
				4739	<div class="source">
				4740	<pre>create-uuid()
				4741	</pre></div></div></li>
				4742
				4743	<li>
				4744	<p>Generates a <tt>uuid</tt>.</p></li>
				4745
				4746	<li>Arguments:
				4747
				4748	<ul>
				4749
				4750	<li>none</li>
				4751	</ul></li>
				4752
				4753	<li>Return Value:
				4754
				4755	<ul>
				4756
				4757	<li>A generated <tt>uuid</tt>.</li>
				4758	</ul></li>
				4759	</ul></div>
				4760	<div class="section">
				4761	<h3><a name="is-null"></a>is-null</h3>
				4762
				4763	<ul>
				4764
				4765	<li>
				4766	<p>Syntax:</p>
				4767
				4768	<div class="source">
				4769	<div class="source">
				4770	<pre>is-null(var)
				4771	</pre></div></div></li>
				4772
				4773	<li>
				4774	<p>Checks whether the given variable is a <tt>null</tt> value.</p></li>
				4775
				4776	<li>Arguments:
				4777
				4778	<ul>
				4779
				4780	<li><tt>var</tt> : A variable (any type is allowed).</li>
				4781	</ul></li>
				4782
				4783	<li>Return Value:
				4784
				4785	<ul>
				4786
				4787	<li>A <tt>boolean</tt> on whether the variable is a <tt>null</tt> or not.</li>
				4788	</ul></li>
				4789
				4790	<li>
				4791	<p>Example:</p>
				4792
				4793	<div class="source">
				4794	<div class="source">
				4795	<pre>for $m in ['hello', 'world', null]
				4796	where not(is-null($m))
				4797	return $m
				4798	</pre></div></div></li>
				4799	</ul>
				4800
				4801	<ul>
				4802
				4803	<li>
				4804	<p>The expected result is:</p>
				4805
				4806	<div class="source">
				4807	<div class="source">
				4808	<pre>"hello"
				4809	"world"
				4810	</pre></div></div></li>
				4811	</ul></div>
				4812	<div class="section">
				4813	<h3><a name="is-system-null"></a>is-system-null</h3>
				4814
				4815	<ul>
				4816
				4817	<li>
				4818	<p>Syntax:</p>
				4819
				4820	<div class="source">
				4821	<div class="source">
				4822	<pre>is-system-null(var)
				4823	</pre></div></div></li>
				4824
				4825	<li>
				4826	<p>Checks whether the given variable is a <tt>system null</tt> value.</p></li>
				4827
				4828	<li>Arguments:
				4829
				4830	<ul>
				4831
				4832	<li><tt>var</tt> : A variable (any type is allowed).</li>
				4833	</ul></li>
				4834
				4835	<li>Return Value:
				4836
				4837	<ul>
				4838
				4839	<li>A <tt>boolean</tt> on whether the variable is a <tt>system null</tt> or not.</li>
				4840	</ul></li>
				4841	</ul></div>
				4842	<div class="section">
				4843	<h3><a name="len"></a>len</h3>
				4844
				4845	<ul>
				4846
				4847	<li>
				4848	<p>Syntax:</p>
				4849	<p>len(list_expression)</p></li>
				4850
				4851	<li>
				4852	<p>Returns the length of the list list_expression.</p></li>
				4853
				4854	<li>Arguments:
				4855
				4856	<ul>
				4857
				4858	<li><tt>list_expression</tt> : An <tt>OrderedList</tt>, <tt>UnorderedList</tt> or <tt>null</tt>, represents the list need to be checked.</li>
				4859	</ul></li>
				4860
				4861	<li>Return Value:
				4862
				4863	<ul>
				4864
				4865	<li>An <tt>Int32</tt> that represents the length of list_expression.</li>
				4866	</ul></li>
				4867
				4868	<li>
				4869	<p>Example:</p>
				4870
				4871	<div class="source">
				4872	<div class="source">
				4873	<pre>use dataverse TinySocial;
				4874
				4875	let $l := ["ASTERIX", "Hyracks"]
				4876	return len($l)
				4877	</pre></div></div></li>
				4878	</ul>
				4879
				4880	<ul>
				4881
				4882	<li>
				4883	<p>The expected result is:</p>
				4884
				4885	<div class="source">
				4886	<div class="source">
				4887	<pre>2
				4888	</pre></div></div></li>
				4889	</ul></div>
				4890	<div class="section">
				4891	<h3><a name="not"></a>not</h3>
				4892
				4893	<ul>
				4894
				4895	<li>
				4896	<p>Syntax:</p>
				4897
				4898	<div class="source">
				4899	<div class="source">
				4900	<pre>not(var)
				4901	</pre></div></div></li>
				4902
				4903	<li>
				4904	<p>Inverts a <tt>boolean</tt> value</p></li>
				4905
				4906	<li>Arguments:
				4907
				4908	<ul>
				4909
				4910	<li><tt>var</tt> : A <tt>boolean</tt> (or <tt>null</tt>)</li>
				4911	</ul></li>
				4912
				4913	<li>Return Value:
				4914
				4915	<ul>
				4916
				4917	<li>A <tt>boolean</tt>, the inverse of <tt>var</tt>. returns <tt>null</tt> if <tt>var</tt> is null</li>
				4918	</ul></li>
				4919
				4920	<li>
				4921	<p>Example:</p>
				4922
				4923	<div class="source">
				4924	<div class="source">
				4925	<pre>for $m in ['hello', 'world', null]
				4926	where not(is-null($m))
				4927	return $m
				4928	</pre></div></div></li>
				4929
				4930	<li>
				4931	<p>The expected result is:</p>
				4932
				4933	<div class="source">
				4934	<div class="source">
				4935	<pre>"hello"
				4936	"world"
				4937	</pre></div></div></li>
				4938	</ul></div>
				4939	<div class="section">
				4940	<h3><a name="range"></a>range</h3>
				4941
				4942	<ul>
				4943
				4944	<li>
				4945	<p>Syntax:</p>
				4946
				4947	<div class="source">
				4948	<div class="source">
				4949	<pre>range(start_numeric_expression, end_numeric_expression)
				4950	</pre></div></div></li>
				4951
				4952	<li>
				4953	<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>
				4954
				4955	<li>Arguments:</li>
				4956
				4957	<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>
				4958
				4959	<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>
				4960
				4961	<li>Return Value:
				4962
				4963	<ul>
				4964
				4965	<li>A generated <tt>uuid</tt>.</li>
				4966	</ul></li>
				4967
				4968	<li>
				4969	<p>Example:</p>
				4970
				4971	<div class="source">
				4972	<div class="source">
				4973	<pre>for $i in range(0, 3)
				4974	return $i;
				4975	</pre></div></div></li>
				4976
				4977	<li>
				4978	<p>The expected result is:</p>
				4979
				4980	<div class="source">
				4981	<div class="source">
				4982	<pre>[ 0
				4983	, 1
				4984	, 2
				4985	, 3
				4986	]
				4987	</pre></div></div></li>
				4988	</ul></div>
				4989	<div class="section">
				4990	<h3><a name="switch-case"></a>switch-case</h3>
				4991
				4992	<ul>
				4993
				4994	<li>
				4995	<p>Syntax:</p>
				4996
				4997	<div class="source">
				4998	<div class="source">
				4999	<pre>switch-case(condition,
				5000	case1, case1-result,
				5001	case2, case2-result,
				5002	...,
				5003	default, default-result
				5004	)
				5005	</pre></div></div></li>
				5006
				5007	<li>
				5008	<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>
				5009
				5010	<li>Arguments:
				5011
				5012	<ul>
				5013
				5014	<li><tt>condition</tt>: A variable (any type is allowed).</li>
				5015
				5016	<li><tt>caseI/default</tt>: A variable (any type is allowed).</li>
				5017
				5018	<li><tt>caseI/default-result</tt>: A variable (any type is allowed).</li>
				5019	</ul></li>
				5020
				5021	<li>Return Value:
				5022
				5023	<ul>
				5024
				5025	<li>Returns <tt>caseI-result</tt> if <tt>condition</tt> matches <tt>caseI</tt>, otherwise <tt>default-result</tt>.</li>
				5026	</ul></li>
				5027
				5028	<li>
				5029	<p>Example 1:</p>
				5030
				5031	<div class="source">
				5032	<div class="source">
				5033	<pre>switch-case("a",
				5034	"a", 0,
				5035	"x", 1,
				5036	"y", 2,
				5037	"z", 3
				5038	)
				5039	</pre></div></div></li>
				5040	</ul>
				5041
				5042	<ul>
				5043
				5044	<li>
				5045	<p>The expected result is:</p>
				5046
				5047	<div class="source">
				5048	<div class="source">
				5049	<pre>0
				5050	</pre></div></div></li>
				5051
				5052	<li>
				5053	<p>Example 2:</p>
				5054
				5055	<div class="source">
				5056	<div class="source">
				5057	<pre>switch-case("a",
				5058	"x", 1,
				5059	"y", 2,
				5060	"z", 3
				5061	)
				5062	</pre></div></div></li>
				5063
				5064	<li>
				5065	<p>The expected result is:</p>
				5066
				5067	<div class="source">
				5068	<div class="source">
				5069	<pre>3
				5070	</pre></div></div></li>
				5071	</ul></div></div>
				5072	</div>
				5073	</div>
				5074	</div>
				5075
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				5080	<div class="row span12">Copyright © 2016
				5081	<a href="http://www.apache.org/">The Apache Software Foundation</a>.
				5082	All Rights Reserved.
				5083
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