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				206	! --><h1>Asterix: Using Functions</h1>
				207	<div class="section">
				208	<h2><a name="Table_of_Contents"></a><a name="toc" id="toc">Table of Contents</a></h2>
				209
				210	<ul>
				211
				212	<li><a href="#NumericFunctions">Numeric Functions</a></li>
				213
				214	<li><a href="#StringFunctions">String Functions</a></li>
				215
				216	<li><a href="#AggregateFunctions">Aggregate Functions</a></li>
				217
				218	<li><a href="#SpatialFunctions">Spatial Functions</a></li>
				219
				220	<li><a href="#SimilarityFunctions">Similarity Functions</a></li>
				221
				222	<li><a href="#TokenizingFunctions">Tokenizing Functions</a></li>
				223
				224	<li><a href="#TemporalFunctions">Temporal Functions</a></li>
				225
				226	<li><a href="#RecordFunctions">Record Functions</a></li>
				227
				228	<li><a href="#OtherFunctions">Other Functions</a></li>
				229	</ul>
				230	<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>
				231	<div class="section">
				232	<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>
				233	<div class="section">
				234	<h3><a name="abs"></a>abs</h3>
				235
				236	<ul>
				237
				238	<li>
				239	<p>Syntax:</p>
				240
				241	<div class="source">
				242	<div class="source">
				243	<pre>abs(numeric_expression)
				244	</pre></div></div></li>
				245
				246	<li>
				247	<p>Computes the absolute value of the argument.</p></li>
				248
				249	<li>Arguments:
				250
				251	<ul>
				252
				253	<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>
				254	</ul></li>
				255
				256	<li>Return Value:
				257
				258	<ul>
				259
				260	<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>
				261	</ul></li>
				262
				263	<li>
				264	<p>Example:</p>
				265
				266	<div class="source">
				267	<div class="source">
				268	<pre>let $v1 := abs(2013)
				269	let $v2 := abs(-4036)
				270	let $v3 := abs(0)
				271	let $v4 := abs(float("-2013.5"))
				272	let $v5 := abs(double("-2013.593823748327284"))
				273	return { "v1": $v1, "v2": $v2, "v3": $v3, "v4": $v4, "v5": $v5 }
				274	</pre></div></div></li>
				275	</ul>
				276
				277	<ul>
				278
				279	<li>
				280	<p>The expected result is:</p>
				281
				282	<div class="source">
				283	<div class="source">
				284	<pre>{ "v1": 2013, "v2": 4036, "v3": 0, "v4": 2013.5f, "v5": 2013.5938237483274d }
				285	</pre></div></div></li>
				286	</ul></div>
				287	<div class="section">
				288	<h3><a name="ceiling"></a>ceiling</h3>
				289
				290	<ul>
				291
				292	<li>
				293	<p>Syntax:</p>
				294
				295	<div class="source">
				296	<div class="source">
				297	<pre>ceiling(numeric_expression)
				298	</pre></div></div></li>
				299
				300	<li>
				301	<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>
				302
				303	<li>Arguments:
				304
				305	<ul>
				306
				307	<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>
				308	</ul></li>
				309
				310	<li>Return Value:
				311
				312	<ul>
				313
				314	<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>
				315	</ul></li>
				316
				317	<li>
				318	<p>Example:</p>
				319
				320	<div class="source">
				321	<div class="source">
				322	<pre>let $v1 := ceiling(2013)
				323	let $v2 := ceiling(-4036)
				324	let $v3 := ceiling(0.3)
				325	let $v4 := ceiling(float("-2013.2"))
				326	let $v5 := ceiling(double("-2013.893823748327284"))
				327	return { "v1": $v1, "v2": $v2, "v3": $v3, "v4": $v4, "v5": $v5 }
				328	</pre></div></div></li>
				329	</ul>
				330
				331	<ul>
				332
				333	<li>
				334	<p>The expected result is:</p>
				335
				336	<div class="source">
				337	<div class="source">
				338	<pre>{ "v1": 2013, "v2": -4036, "v3": 1.0d, "v4": -2013.0f, "v5": -2013.0d }
				339	</pre></div></div></li>
				340	</ul></div>
				341	<div class="section">
				342	<h3><a name="floor"></a>floor</h3>
				343
				344	<ul>
				345
				346	<li>
				347	<p>Syntax:</p>
				348
				349	<div class="source">
				350	<div class="source">
				351	<pre>floor(numeric_expression)
				352	</pre></div></div></li>
				353
				354	<li>
				355	<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>
				356
				357	<li>Arguments:
				358
				359	<ul>
				360
				361	<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>
				362	</ul></li>
				363
				364	<li>Return Value:
				365
				366	<ul>
				367
				368	<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>
				369	</ul></li>
				370
				371	<li>
				372	<p>Example:</p>
				373
				374	<div class="source">
				375	<div class="source">
				376	<pre>let $v1 := floor(2013)
				377	let $v2 := floor(-4036)
				378	let $v3 := floor(0.8)
				379	let $v4 := floor(float("-2013.2"))
				380	let $v5 := floor(double("-2013.893823748327284"))
				381	return { "v1": $v1, "v2": $v2, "v3": $v3, "v4": $v4, "v5": $v5 }
				382	</pre></div></div></li>
				383	</ul>
				384
				385	<ul>
				386
				387	<li>
				388	<p>The expected result is:</p>
				389
				390	<div class="source">
				391	<div class="source">
				392	<pre>{ "v1": 2013, "v2": -4036, "v3": 0.0d, "v4": -2014.0f, "v5": -2014.0d }
				393	</pre></div></div></li>
				394	</ul></div>
				395	<div class="section">
				396	<h3><a name="round"></a>round</h3>
				397
				398	<ul>
				399
				400	<li>
				401	<p>Syntax:</p>
				402
				403	<div class="source">
				404	<div class="source">
				405	<pre>round(numeric_expression)
				406	</pre></div></div></li>
				407
				408	<li>
				409	<p>Computes the number with no fractional part that is closest (and also closest to positive infinity) to the argument.</p></li>
				410
				411	<li>Arguments:
				412
				413	<ul>
				414
				415	<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>
				416	</ul></li>
				417
				418	<li>Return Value:
				419
				420	<ul>
				421
				422	<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>
				423	</ul></li>
				424
				425	<li>
				426	<p>Example:</p>
				427
				428	<div class="source">
				429	<div class="source">
				430	<pre>let $v1 := round(2013)
				431	let $v2 := round(-4036)
				432	let $v3 := round(0.8)
				433	let $v4 := round(float("-2013.256"))
				434	let $v5 := round(double("-2013.893823748327284"))
				435	return { "v1": $v1, "v2": $v2, "v3": $v3, "v4": $v4, "v5": $v5 }
				436	</pre></div></div></li>
				437	</ul>
				438
				439	<ul>
				440
				441	<li>
				442	<p>The expected result is:</p>
				443
				444	<div class="source">
				445	<div class="source">
				446	<pre>{ "v1": 2013, "v2": -4036, "v3": 1.0d, "v4": -2013.0f, "v5": -2014.0d }
				447	</pre></div></div></li>
				448	</ul></div>
				449	<div class="section">
				450	<h3><a name="round-half-to-even"></a>round-half-to-even</h3>
				451
				452	<ul>
				453
				454	<li>
				455	<p>Syntax:</p>
				456
				457	<div class="source">
				458	<div class="source">
				459	<pre>round-half-to-even(numeric_expression, [precision])
				460	</pre></div></div></li>
				461
				462	<li>
				463	<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>
				464
				465	<li>Arguments:
				466
				467	<ul>
				468
				469	<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>
				470
				471	<li><tt>precision</tt>: An optional integer field representing the number of digits in the fraction of the the result</li>
				472	</ul></li>
				473
				474	<li>Return Value:
				475
				476	<ul>
				477
				478	<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>
				479	</ul></li>
				480
				481	<li>
				482	<p>Example:</p>
				483
				484	<div class="source">
				485	<div class="source">
				486	<pre>let $v1 := round-half-to-even(2013)
				487	let $v2 := round-half-to-even(-4036)
				488	let $v3 := round-half-to-even(0.8)
				489	let $v4 := round-half-to-even(float("-2013.256"))
				490	let $v5 := round-half-to-even(double("-2013.893823748327284"))
				491	let $v6 := round-half-to-even(double("-2013.893823748327284"), 2)
				492	let $v7 := round-half-to-even(2013, 4)
				493	let $v8 := round-half-to-even(float("-2013.256"), 5)
				494	return { "v1": $v1, "v2": $v2, "v3": $v3, "v4": $v4, "v5": $v5, "v6": $v6, "v7": $v7, "v8": $v8 }
				495	</pre></div></div></li>
				496	</ul>
				497
				498	<ul>
				499
				500	<li>
				501	<p>The expected result is:</p>
				502
				503	<div class="source">
				504	<div class="source">
				505	<pre>{ "v1": 2013, "v2": -4036, "v3": 1.0d, "v4": -2013.0f, "v5": -2014.0d, "v6": -2013.89d, "v7": 2013, "v8": -2013.256f }
				506	</pre></div></div></li>
				507	</ul></div></div>
				508	<div class="section">
				509	<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>
				510	<div class="section">
				511	<h3><a name="string-to-codepoint"></a>string-to-codepoint</h3>
				512
				513	<ul>
				514
				515	<li>
				516	<p>Syntax:</p>
				517
				518	<div class="source">
				519	<div class="source">
				520	<pre>string-to-codepoint(string_expression)
				521	</pre></div></div></li>
				522
				523	<li>
				524	<p>Converts the string <tt>string_expression</tt> to its code-based representation.</p></li>
				525
				526	<li>Arguments:
				527
				528	<ul>
				529
				530	<li><tt>string_expression</tt> : A <tt>string</tt> that will be converted.</li>
				531	</ul></li>
				532
				533	<li>Return Value:
				534
				535	<ul>
				536
				537	<li>An <tt>OrderedList</tt> of the code points for the string <tt>string_expression</tt>.</li>
				538	</ul></li>
				539	</ul></div>
				540	<div class="section">
				541	<h3><a name="codepoint-to-string"></a>codepoint-to-string</h3>
				542
				543	<ul>
				544
				545	<li>
				546	<p>Syntax:</p>
				547
				548	<div class="source">
				549	<div class="source">
				550	<pre>codepoint-to-string(list_expression)
				551	</pre></div></div></li>
				552
				553	<li>
				554	<p>Converts the ordered code-based representation <tt>list_expression</tt> to the corresponding string.</p></li>
				555
				556	<li>Arguments:
				557
				558	<ul>
				559
				560	<li><tt>list_expression</tt> : An <tt>OrderedList</tt> of code-points.</li>
				561	</ul></li>
				562
				563	<li>Return Value:
				564
				565	<ul>
				566
				567	<li>A <tt>string</tt> representation of <tt>list_expression</tt>.</li>
				568	</ul></li>
				569
				570	<li>
				571	<p>Example:</p>
				572
				573	<div class="source">
				574	<div class="source">
				575	<pre>use dataverse TinySocial;
				576
				577	let $s := "Hello ASTERIX!"
				578	let $l := string-to-codepoint($s)
				579	let $ss := codepoint-to-string($l)
				580	return {"codes": $l, "string": $ss}
				581	</pre></div></div></li>
				582	</ul>
				583
				584	<ul>
				585
				586	<li>
				587	<p>The expected result is:</p>
				588
				589	<div class="source">
				590	<div class="source">
				591	<pre>{ "codes": [ 72, 101, 108, 108, 111, 32, 65, 83, 84, 69, 82, 73, 88, 33 ], "string": "Hello ASTERIX!" }
				592	</pre></div></div></li>
				593	</ul></div>
				594	<div class="section">
				595	<h3><a name="contains"></a>contains</h3>
				596
				597	<ul>
				598
				599	<li>
				600	<p>Syntax:</p>
				601
				602	<div class="source">
				603	<div class="source">
				604	<pre>contains(string_expression, substring_to_contain)
				605	</pre></div></div></li>
				606
				607	<li>
				608	<p>Checks whether the string <tt>string_expression</tt> contains the string <tt>substring_to_contain</tt></p></li>
				609
				610	<li>Arguments:
				611
				612	<ul>
				613
				614	<li><tt>string_expression</tt> : A <tt>string</tt> that might contain the given substring.</li>
				615
				616	<li><tt>substring_to_contain</tt> : A target <tt>string</tt> that might be contained.</li>
				617	</ul></li>
				618
				619	<li>Return Value:
				620
				621	<ul>
				622
				623	<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>
				624	</ul></li>
				625
				626	<li>Note: An <a href="similarity.html#UsingIndexesToSupportSimilarityQueries">n-gram index</a> can be utilized for this function.</li>
				627
				628	<li>
				629	<p>Example:</p>
				630
				631	<div class="source">
				632	<div class="source">
				633	<pre>use dataverse TinySocial;
				634
				635	for $i in dataset('FacebookMessages')
				636	where contains($i.message, "phone")
				637	return {"mid": $i.message-id, "message": $i.message}
				638	</pre></div></div></li>
				639	</ul>
				640
				641	<ul>
				642
				643	<li>
				644	<p>The expected result is:</p>
				645
				646	<div class="source">
				647	<div class="source">
				648	<pre>{ "mid": 2, "message": " dislike iphone its touch-screen is horrible" }
				649	{ "mid": 13, "message": " dislike iphone the voice-command is bad:(" }
				650	{ "mid": 15, "message": " like iphone the voicemail-service is awesome" }
				651	</pre></div></div></li>
				652	</ul></div>
				653	<div class="section">
				654	<h3><a name="like"></a>like</h3>
				655
				656	<ul>
				657
				658	<li>
				659	<p>Syntax:</p>
				660
				661	<div class="source">
				662	<div class="source">
				663	<pre>like(string_expression, string_pattern)
				664	</pre></div></div></li>
				665
				666	<li>
				667	<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>
				668
				669	<li>Arguments:
				670
				671	<ul>
				672
				673	<li><tt>string_expression</tt> : A <tt>string</tt> that might contain the pattern or <tt>null</tt>.</li>
				674
				675	<li><tt>string_pattern</tt> : A pattern <tt>string</tt> that might be contained or <tt>null</tt>.</li>
				676	</ul></li>
				677
				678	<li>Return Value:
				679
				680	<ul>
				681
				682	<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>
				683	</ul></li>
				684
				685	<li>
				686	<p>Example:</p>
				687
				688	<div class="source">
				689	<div class="source">
				690	<pre>use dataverse TinySocial;
				691
				692	for $i in dataset('FacebookMessages')
				693	where like($i.message, "%at&t%")
				694	return $i.message
				695	</pre></div></div></li>
				696	</ul>
				697
				698	<ul>
				699
				700	<li>
				701	<p>The expected result is:</p>
				702
				703	<div class="source">
				704	<div class="source">
				705	<pre>" can't stand at&t the network is horrible:("
				706	" can't stand at&t its plan is terrible"
				707	" love at&t its 3G is good:)"
				708	</pre></div></div></li>
				709	</ul></div>
				710	<div class="section">
				711	<h3><a name="starts-with"></a>starts-with</h3>
				712
				713	<ul>
				714
				715	<li>
				716	<p>Syntax:</p>
				717
				718	<div class="source">
				719	<div class="source">
				720	<pre>starts-with(string_expression, substring_to_start_with)
				721	</pre></div></div></li>
				722
				723	<li>
				724	<p>Checks whether the string <tt>string_expression</tt> starts with the string <tt>substring_to_start_with</tt>.</p></li>
				725
				726	<li>Arguments:
				727
				728	<ul>
				729
				730	<li><tt>string_expression</tt> : A <tt>string</tt> that might start with the given string.</li>
				731
				732	<li><tt>substring_to_start_with</tt> : A <tt>string</tt> that might be contained as the starting substring.</li>
				733	</ul></li>
				734
				735	<li>Return Value:
				736
				737	<ul>
				738
				739	<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>
				740	</ul></li>
				741
				742	<li>
				743	<p>Example:</p>
				744
				745	<div class="source">
				746	<div class="source">
				747	<pre>use dataverse TinySocial;
				748
				749	for $i in dataset('FacebookMessages')
				750	where starts-with($i.message, " like")
				751	return $i.message
				752	</pre></div></div></li>
				753	</ul>
				754
				755	<ul>
				756
				757	<li>
				758	<p>The expected result is:</p>
				759
				760	<div class="source">
				761	<div class="source">
				762	<pre>" like samsung the plan is amazing"
				763	" like t-mobile its platform is mind-blowing"
				764	" like verizon the 3G is awesome:)"
				765	" like iphone the voicemail-service is awesome"
				766	</pre></div></div></li>
				767	</ul></div>
				768	<div class="section">
				769	<h3><a name="ends-with"></a>ends-with</h3>
				770
				771	<ul>
				772
				773	<li>
				774	<p>Syntax:</p>
				775
				776	<div class="source">
				777	<div class="source">
				778	<pre>ends-with(string_expression, substring_to_end_with)
				779	</pre></div></div></li>
				780
				781	<li>
				782	<p>Checks whether the string <tt>string_expression</tt> ends with the string <tt>substring_to_end_with</tt>.</p></li>
				783
				784	<li>Arguments:
				785
				786	<ul>
				787
				788	<li><tt>string_expression</tt> : A <tt>string</tt> that might end with the given string.</li>
				789
				790	<li><tt>substring_to_end_with</tt> : A <tt>string</tt> that might be contained as the ending substring.</li>
				791	</ul></li>
				792
				793	<li>Return Value:
				794
				795	<ul>
				796
				797	<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>
				798	</ul></li>
				799
				800	<li>
				801	<p>Example:</p>
				802
				803	<div class="source">
				804	<div class="source">
				805	<pre>use dataverse TinySocial;
				806
				807	for $i in dataset('FacebookMessages')
				808	where ends-with($i.message, ":)")
				809	return $i.message
				810	</pre></div></div></li>
				811	</ul>
				812
				813	<ul>
				814
				815	<li>
				816	<p>The expected result is:</p>
				817
				818	<div class="source">
				819	<div class="source">
				820	<pre>" love sprint its shortcut-menu is awesome:)"
				821	" like verizon the 3G is awesome:)"
				822	" love at&t its 3G is good:)"
				823	</pre></div></div></li>
				824	</ul></div>
				825	<div class="section">
				826	<h3><a name="string-concat"></a>string-concat</h3>
				827
				828	<ul>
				829
				830	<li>
				831	<p>Syntax:</p>
				832
				833	<div class="source">
				834	<div class="source">
				835	<pre>string-concat(list_expression)
				836	</pre></div></div></li>
				837
				838	<li>
				839	<p>Concatenates a list of strings <tt>list_expression</tt> into a single string.</p></li>
				840
				841	<li>Arguments:
				842
				843	<ul>
				844
				845	<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>
				846	</ul></li>
				847
				848	<li>Return Value:
				849
				850	<ul>
				851
				852	<li>Returns the concatenated <tt>string</tt> value.</li>
				853	</ul></li>
				854
				855	<li>
				856	<p>Example:</p>
				857
				858	<div class="source">
				859	<div class="source">
				860	<pre>let $i := "ASTERIX"
				861	let $j := " "
				862	let $k := "ROCKS!"
				863	return string-concat([$i, $j, $k])
				864	</pre></div></div></li>
				865	</ul>
				866
				867	<ul>
				868
				869	<li>
				870	<p>The expected result is:</p>
				871
				872	<div class="source">
				873	<div class="source">
				874	<pre>"ASTERIX ROCKS!"
				875	</pre></div></div></li>
				876	</ul></div>
				877	<div class="section">
				878	<h3><a name="string-join"></a>string-join</h3>
				879
				880	<ul>
				881
				882	<li>
				883	<p>Syntax:</p>
				884
				885	<div class="source">
				886	<div class="source">
				887	<pre>string-join(list_expression, string_expression)
				888	</pre></div></div></li>
				889
				890	<li>
				891	<p>Joins a list of strings <tt>list_expression</tt> with the given separator <tt>string_expression</tt> into a single string.</p></li>
				892
				893	<li>Arguments:
				894
				895	<ul>
				896
				897	<li><tt>list_expression</tt> : An <tt>OrderedList</tt> or <tt>UnorderedList</tt> of strings (could be <tt>null</tt>) to be joined.</li>
				898
				899	<li><tt>string_expression</tt> : A <tt>string</tt> as the separator.</li>
				900	</ul></li>
				901
				902	<li>Return Value:
				903
				904	<ul>
				905
				906	<li>Returns the joined <tt>String</tt>.</li>
				907	</ul></li>
				908
				909	<li>
				910	<p>Example:</p>
				911
				912	<div class="source">
				913	<div class="source">
				914	<pre>use dataverse TinySocial;
				915
				916	let $i := ["ASTERIX", "ROCKS~"]
				917	return string-join($i, "!! ")
				918	</pre></div></div></li>
				919	</ul>
				920
				921	<ul>
				922
				923	<li>
				924	<p>The expected result is:</p>
				925
				926	<div class="source">
				927	<div class="source">
				928	<pre>"ASTERIX!! ROCKS~"
				929	</pre></div></div></li>
				930	</ul></div>
				931	<div class="section">
				932	<h3><a name="lowercase"></a>lowercase</h3>
				933
				934	<ul>
				935
				936	<li>
				937	<p>Syntax:</p>
				938
				939	<div class="source">
				940	<div class="source">
				941	<pre>lowercase(string_expression)
				942	</pre></div></div></li>
				943
				944	<li>
				945	<p>Converts a given string <tt>string_expression</tt> to its lowercase form.</p></li>
				946
				947	<li>Arguments:
				948
				949	<ul>
				950
				951	<li><tt>string_expression</tt> : A <tt>string</tt> to be converted.</li>
				952	</ul></li>
				953
				954	<li>Return Value:
				955
				956	<ul>
				957
				958	<li>Returns a <tt>string</tt> as the lowercase form of the given <tt>string_expression</tt>.</li>
				959	</ul></li>
				960
				961	<li>
				962	<p>Example:</p>
				963
				964	<div class="source">
				965	<div class="source">
				966	<pre>use dataverse TinySocial;
				967
				968	let $i := "ASTERIX"
				969	return lowercase($i)
				970	</pre></div></div></li>
				971	</ul>
				972
				973	<ul>
				974
				975	<li>
				976	<p>The expected result is:</p>
				977
				978	<div class="source">
				979	<div class="source">
				980	<pre>asterix
				981	</pre></div></div></li>
				982	</ul></div>
				983	<div class="section">
				984	<h3><a name="uppercase"></a>uppercase</h3>
				985
				986	<ul>
				987
				988	<li>Syntax:</li>
				989	</ul>
				990	<p>uppercase(string_expression)</p>
				991
				992	<ul>
				993
				994	<li>Converts a given string <tt>string_expression</tt> to its uppercase form.</li>
				995
				996	<li>Arguments:
				997
				998	<ul>
				999
				1000	<li><tt>string_expression</tt> : A <tt>string</tt> to be converted.</li>
				1001	</ul></li>
				1002
				1003	<li>Return Value:
				1004
				1005	<ul>
				1006
				1007	<li>Returns a <tt>string</tt> as the uppercase form of the given <tt>string_expression</tt>.</li>
				1008	</ul></li>
				1009
				1010	<li>
				1011	<p>Example:</p>
				1012
				1013	<div class="source">
				1014	<div class="source">
				1015	<pre>use dataverse TinySocial;
				1016
				1017	let $i := "asterix"
				1018	return uppercase($i)
				1019	</pre></div></div></li>
				1020	</ul>
				1021
				1022	<ul>
				1023
				1024	<li>
				1025	<p>The expected result is:</p>
				1026
				1027	<div class="source">
				1028	<div class="source">
				1029	<pre>ASTERIX
				1030	</pre></div></div></li>
				1031	</ul></div>
				1032	<div class="section">
				1033	<h3><a name="uppercase"></a>uppercase</h3>
				1034
				1035	<ul>
				1036
				1037	<li>
				1038	<p>Syntax:</p>
				1039
				1040	<div class="source">
				1041	<div class="source">
				1042	<pre>uppercase(string_expression)
				1043	</pre></div></div></li>
				1044
				1045	<li>
				1046	<p>Converts a given string <tt>string_expression</tt> to its uppercase form.</p></li>
				1047
				1048	<li>Arguments:
				1049
				1050	<ul>
				1051
				1052	<li><tt>string_expression</tt> : A <tt>string</tt> to be converted.</li>
				1053	</ul></li>
				1054
				1055	<li>Return Value:
				1056
				1057	<ul>
				1058
				1059	<li>Returns a <tt>string</tt> as the uppercase form of the given <tt>string_expression</tt>.</li>
				1060	</ul></li>
				1061
				1062	<li>
				1063	<p>Example:</p>
				1064
				1065	<div class="source">
				1066	<div class="source">
				1067	<pre>use dataverse TinySocial;
				1068
				1069	let $i := "asterix"
				1070	return uppercase($i)
				1071	</pre></div></div></li>
				1072	</ul>
				1073
				1074	<ul>
				1075
				1076	<li>
				1077	<p>The expected result is:</p>
				1078
				1079	<div class="source">
				1080	<div class="source">
				1081	<pre>ASTERIX
				1082	</pre></div></div></li>
				1083	</ul></div>
				1084	<div class="section">
				1085	<h3><a name="matches"></a>matches</h3>
				1086
				1087	<ul>
				1088
				1089	<li>
				1090	<p>Syntax:</p>
				1091
				1092	<div class="source">
				1093	<div class="source">
				1094	<pre>matches(string_expression, string_pattern)
				1095	</pre></div></div></li>
				1096
				1097	<li>
				1098	<p>Checks whether the strings <tt>string_expression</tt> matches the given pattern <tt>string_pattern</tt> (A Java regular expression pattern).</p></li>
				1099
				1100	<li>Arguments:
				1101
				1102	<ul>
				1103
				1104	<li><tt>string_expression</tt> : A <tt>string</tt> that might contain the pattern.</li>
				1105
				1106	<li><tt>string_pattern</tt> : A pattern <tt>string</tt> to be matched.</li>
				1107	</ul></li>
				1108
				1109	<li>Return Value:
				1110
				1111	<ul>
				1112
				1113	<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>
				1114	</ul></li>
				1115
				1116	<li>
				1117	<p>Example:</p>
				1118
				1119	<div class="source">
				1120	<div class="source">
				1121	<pre>use dataverse TinySocial;
				1122
				1123	for $i in dataset('FacebookMessages')
				1124	where matches($i.message, "dislike iphone")
				1125	return $i.message
				1126	</pre></div></div></li>
				1127	</ul>
				1128
				1129	<ul>
				1130
				1131	<li>
				1132	<p>The expected result is:</p>
				1133
				1134	<div class="source">
				1135	<div class="source">
				1136	<pre>" dislike iphone its touch-screen is horrible"
				1137	" dislike iphone the voice-command is bad:("
				1138	</pre></div></div></li>
				1139	</ul></div>
				1140	<div class="section">
				1141	<h3><a name="replace"></a>replace</h3>
				1142
				1143	<ul>
				1144
				1145	<li>
				1146	<p>Syntax:</p>
				1147
				1148	<div class="source">
				1149	<div class="source">
				1150	<pre>replace(string_expression, string_pattern, string_replacement[, string_flags])
				1151	</pre></div></div></li>
				1152
				1153	<li>
				1154	<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>
				1155
				1156	<li>Arguments:
				1157
				1158	<ul>
				1159
				1160	<li><tt>string_expression</tt> : A <tt>string</tt> that might contain the pattern.</li>
				1161
				1162	<li><tt>string_pattern</tt> : A pattern <tt>string</tt> to be matched.</li>
				1163
				1164	<li><tt>string_replacement</tt> : A pattern <tt>string</tt> to be used as the replacement.</li>
				1165
				1166	<li><tt>string_flag</tt> : (Optional) A <tt>string</tt> with flags to be used during replace.</li>
				1167
				1168	<li>The following modes are enabled with these flags: dotall (s), multiline (m), case-insenitive (i), and comments and whitespace (x).</li>
				1169	</ul></li>
				1170
				1171	<li>Return Value:
				1172
				1173	<ul>
				1174
				1175	<li>Returns a <tt>string</tt> that is obtained after the replacements.</li>
				1176	</ul></li>
				1177
				1178	<li>
				1179	<p>Example:</p>
				1180
				1181	<div class="source">
				1182	<div class="source">
				1183	<pre>use dataverse TinySocial;
				1184
				1185	for $i in dataset('FacebookMessages')
				1186	where matches($i.message, " like iphone")
				1187	return replace($i.message, " like iphone", "like android")
				1188	</pre></div></div></li>
				1189	</ul>
				1190
				1191	<ul>
				1192
				1193	<li>
				1194	<p>The expected result is:</p>
				1195
				1196	<div class="source">
				1197	<div class="source">
				1198	<pre>"like android the voicemail-service is awesome"
				1199	</pre></div></div></li>
				1200	</ul></div>
				1201	<div class="section">
				1202	<h3><a name="string-length"></a>string-length</h3>
				1203
				1204	<ul>
				1205
				1206	<li>
				1207	<p>Syntax:</p>
				1208
				1209	<div class="source">
				1210	<div class="source">
				1211	<pre>string-length(string_expression)
				1212	</pre></div></div></li>
				1213
				1214	<li>
				1215	<p>Returns the length of the string <tt>string_expression</tt>.</p></li>
				1216
				1217	<li>Arguments:
				1218
				1219	<ul>
				1220
				1221	<li><tt>string_expression</tt> : A <tt>string</tt> or <tt>null</tt> that represents the string to be checked.</li>
				1222	</ul></li>
				1223
				1224	<li>Return Value:
				1225
				1226	<ul>
				1227
				1228	<li>An <tt>int64</tt> that represents the length of <tt>string_expression</tt>.</li>
				1229	</ul></li>
				1230
				1231	<li>
				1232	<p>Example:</p>
				1233
				1234	<div class="source">
				1235	<div class="source">
				1236	<pre>use dataverse TinySocial;
				1237
				1238	for $i in dataset('FacebookMessages')
				1239	return {"mid": $i.message-id, "message-len": string-length($i.message)}
				1240	</pre></div></div></li>
				1241	</ul>
				1242
				1243	<ul>
				1244
				1245	<li>
				1246	<p>The expected result is:</p>
				1247
				1248	<div class="source">
				1249	<div class="source">
				1250	<pre>{ "mid": 1, "message-len": 43 }
				1251	{ "mid": 2, "message-len": 44 }
				1252	{ "mid": 3, "message-len": 33 }
				1253	{ "mid": 4, "message-len": 43 }
				1254	{ "mid": 5, "message-len": 46 }
				1255	{ "mid": 6, "message-len": 43 }
				1256	{ "mid": 7, "message-len": 37 }
				1257	{ "mid": 8, "message-len": 33 }
				1258	{ "mid": 9, "message-len": 34 }
				1259	{ "mid": 10, "message-len": 50 }
				1260	{ "mid": 11, "message-len": 38 }
				1261	{ "mid": 12, "message-len": 52 }
				1262	{ "mid": 13, "message-len": 42 }
				1263	{ "mid": 14, "message-len": 27 }
				1264	{ "mid": 15, "message-len": 45 }
				1265	</pre></div></div></li>
				1266	</ul></div>
				1267	<div class="section">
				1268	<h3><a name="substring"></a>substring</h3>
				1269
				1270	<ul>
				1271
				1272	<li>
				1273	<p>Syntax:</p>
				1274
				1275	<div class="source">
				1276	<div class="source">
				1277	<pre>substring(string_expression, offset[, length])
				1278	</pre></div></div></li>
				1279
				1280	<li>
				1281	<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>
				1282
				1283	<li>Arguments:
				1284
				1285	<ul>
				1286
				1287	<li><tt>string_expression</tt> : A <tt>string</tt> to be extracted.</li>
				1288
				1289	<li><tt>offset</tt> : An <tt>int64</tt> as the starting offset of the substring in <tt>string_expression</tt>.</li>
				1290
				1291	<li><tt>length</tt> : (Optional) An <tt>int64</tt> as the length of the substring.</li>
				1292	</ul></li>
				1293
				1294	<li>Return Value:
				1295
				1296	<ul>
				1297
				1298	<li>A <tt>string</tt> that represents the substring.</li>
				1299	</ul></li>
				1300
				1301	<li>
				1302	<p>Example:</p>
				1303
				1304	<div class="source">
				1305	<div class="source">
				1306	<pre>use dataverse TinySocial;
				1307
				1308	for $i in dataset('FacebookMessages')
				1309	where string-length($i.message) > 50
				1310	return substring($i.message, 50)
				1311	</pre></div></div></li>
				1312	</ul>
				1313
				1314	<ul>
				1315
				1316	<li>
				1317	<p>The expected result is:</p>
				1318
				1319	<div class="source">
				1320	<div class="source">
				1321	<pre>"G:("
				1322	</pre></div></div></li>
				1323	</ul></div>
				1324	<div class="section">
				1325	<h3><a name="substring-before"></a>substring-before</h3>
				1326
				1327	<ul>
				1328
				1329	<li>
				1330	<p>Syntax:</p>
				1331
				1332	<div class="source">
				1333	<div class="source">
				1334	<pre>substring-before(string_expression, string_pattern)
				1335	</pre></div></div></li>
				1336
				1337	<li>
				1338	<p>Returns the substring from the given string <tt>string_expression</tt> before the given pattern <tt>string_pattern</tt>.</p></li>
				1339
				1340	<li>Arguments:
				1341
				1342	<ul>
				1343
				1344	<li><tt>string_expression</tt> : A <tt>string</tt> to be extracted.</li>
				1345
				1346	<li><tt>string_pattern</tt> : A <tt>string</tt> pattern to be searched.</li>
				1347	</ul></li>
				1348
				1349	<li>Return Value:
				1350
				1351	<ul>
				1352
				1353	<li>A <tt>string</tt> that represents the substring.</li>
				1354	</ul></li>
				1355
				1356	<li>
				1357	<p>Example:</p>
				1358
				1359	<div class="source">
				1360	<div class="source">
				1361	<pre>use dataverse TinySocial;
				1362
				1363	for $i in dataset('FacebookMessages')
				1364	where contains($i.message, "iphone")
				1365	return substring-before($i.message, "iphone")
				1366	</pre></div></div></li>
				1367	</ul>
				1368
				1369	<ul>
				1370
				1371	<li>
				1372	<p>The expected result is:</p>
				1373
				1374	<div class="source">
				1375	<div class="source">
				1376	<pre>" dislike "
				1377	" dislike "
				1378	" like "
				1379	</pre></div></div></li>
				1380	</ul></div>
				1381	<div class="section">
				1382	<h3><a name="substring-after"></a>substring-after</h3>
				1383
				1384	<ul>
				1385
				1386	<li>
				1387	<p>Syntax:</p>
				1388
				1389	<div class="source">
				1390	<div class="source">
				1391	<pre>substring-after(string_expression, string_pattern)
				1392	</pre></div></div></li>
				1393
				1394	<li>
				1395	<p>Returns the substring from the given string <tt>string_expression</tt> after the given pattern <tt>string_pattern</tt>.</p></li>
				1396
				1397	<li>Arguments:
				1398
				1399	<ul>
				1400
				1401	<li><tt>string_expression</tt> : A <tt>string</tt> to be extracted.</li>
				1402
				1403	<li><tt>string_pattern</tt> : A <tt>string</tt> pattern to be searched.</li>
				1404	</ul></li>
				1405
				1406	<li>Return Value:
				1407
				1408	<ul>
				1409
				1410	<li>A <tt>string</tt> that represents the substring.</li>
				1411	</ul></li>
				1412
				1413	<li>
				1414	<p>Example:</p>
				1415
				1416	<div class="source">
				1417	<div class="source">
				1418	<pre>use dataverse TinySocial;
				1419
				1420	for $i in dataset('FacebookMessages')
				1421	where contains($i.message, "iphone")
				1422	return substring-after($i.message, "iphone")
				1423	</pre></div></div></li>
				1424	</ul>
				1425
				1426	<ul>
				1427
				1428	<li>
				1429	<p>The expected result is:</p>
				1430
				1431	<div class="source">
				1432	<div class="source">
				1433	<pre>" its touch-screen is horrible"
				1434	" the voice-command is bad:("
				1435	" the voicemail-service is awesome"
				1436	</pre></div></div></li>
				1437	</ul></div></div>
				1438	<div class="section">
				1439	<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>
				1440	<div class="section">
				1441	<h3><a name="count"></a>count</h3>
				1442
				1443	<ul>
				1444
				1445	<li>
				1446	<p>Syntax:</p>
				1447
				1448	<div class="source">
				1449	<div class="source">
				1450	<pre>count(list)
				1451	</pre></div></div></li>
				1452
				1453	<li>
				1454	<p>Gets the number of items in the given list.</p></li>
				1455
				1456	<li>Arguments:
				1457
				1458	<ul>
				1459
				1460	<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>
				1461	</ul></li>
				1462
				1463	<li>Return Value:
				1464
				1465	<ul>
				1466
				1467	<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>
				1468	</ul></li>
				1469
				1470	<li>
				1471	<p>Example:</p>
				1472
				1473	<div class="source">
				1474	<div class="source">
				1475	<pre>use dataverse TinySocial;
				1476
				1477	let $l1 := ['hello', 'world', 1, 2, 3]
				1478	let $l2 := for $i in dataset TwitterUsers return $i
				1479	return {"count1": count($l1), "count2": count($l2)}
				1480	</pre></div></div></li>
				1481
				1482	<li>
				1483	<p>The expected result is:</p>
				1484
				1485	<div class="source">
				1486	<div class="source">
				1487	<pre>{ "count1": 5i64, "count2": 4i64 }
				1488	</pre></div></div></li>
				1489	</ul></div>
				1490	<div class="section">
				1491	<h3><a name="avg"></a>avg</h3>
				1492
				1493	<ul>
				1494
				1495	<li>
				1496	<p>Syntax:</p>
				1497
				1498	<div class="source">
				1499	<div class="source">
				1500	<pre>avg(num_list)
				1501	</pre></div></div></li>
				1502
				1503	<li>
				1504	<p>Gets the average value of the items in the given list.</p></li>
				1505
				1506	<li>Arguments:
				1507
				1508	<ul>
				1509
				1510	<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>
				1511	</ul></li>
				1512
				1513	<li>Return Value:
				1514
				1515	<ul>
				1516
				1517	<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>
				1518	</ul></li>
				1519
				1520	<li>
				1521	<p>Example:</p>
				1522
				1523	<div class="source">
				1524	<div class="source">
				1525	<pre>use dataverse TinySocial;
				1526
				1527	let $l := for $i in dataset TwitterUsers return $i.friends_count
				1528	return {"avg_friend_count": avg($l)}
				1529	</pre></div></div></li>
				1530
				1531	<li>
				1532	<p>The expected result is:</p>
				1533
				1534	<div class="source">
				1535	<div class="source">
				1536	<pre>{ "avg_friend_count": 191.5d }
				1537	</pre></div></div></li>
				1538	</ul></div>
				1539	<div class="section">
				1540	<h3><a name="sum"></a>sum</h3>
				1541
				1542	<ul>
				1543
				1544	<li>
				1545	<p>Syntax:</p>
				1546
				1547	<div class="source">
				1548	<div class="source">
				1549	<pre>sum(num_list)
				1550	</pre></div></div></li>
				1551
				1552	<li>
				1553	<p>Gets the sum of the items in the given list.</p></li>
				1554
				1555	<li>Arguments:
				1556
				1557	<ul>
				1558
				1559	<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>
				1560	</ul></li>
				1561
				1562	<li>Return Value:
				1563
				1564	<ul>
				1565
				1566	<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>
				1567	</ul></li>
				1568
				1569	<li>
				1570	<p>Example:</p>
				1571
				1572	<div class="source">
				1573	<div class="source">
				1574	<pre>use dataverse TinySocial;
				1575
				1576	let $l := for $i in dataset TwitterUsers return $i.friends_count
				1577	return {"sum_friend_count": sum($l)}
				1578	</pre></div></div></li>
				1579
				1580	<li>
				1581	<p>The expected result is:</p>
				1582
				1583	<div class="source">
				1584	<div class="source">
				1585	<pre>{ "sum_friend_count": 766 }
				1586	</pre></div></div></li>
				1587	</ul></div>
				1588	<div class="section">
				1589	<h3><a name="minmax"></a>min/max</h3>
				1590
				1591	<ul>
				1592
				1593	<li>
				1594	<p>Syntax:</p>
				1595
				1596	<div class="source">
				1597	<div class="source">
				1598	<pre>min(num_list), max(num_list)
				1599	</pre></div></div></li>
				1600
				1601	<li>
				1602	<p>Gets the min/max value of numeric items in the given list.</p></li>
				1603
				1604	<li>Arguments:
				1605
				1606	<ul>
				1607
				1608	<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>
				1609	</ul></li>
				1610
				1611	<li>Return Value:
				1612
				1613	<ul>
				1614
				1615	<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>
				1616	</ul></li>
				1617
				1618	<li>
				1619	<p>Example:</p>
				1620
				1621	<div class="source">
				1622	<div class="source">
				1623	<pre>use dataverse TinySocial;
				1624
				1625	let $l := for $i in dataset TwitterUsers return $i. friends_count
				1626	return {"min_friend_count": min($l), "max_friend_count": max($l)}
				1627	</pre></div></div></li>
				1628
				1629	<li>
				1630	<p>The expected result is:</p>
				1631
				1632	<div class="source">
				1633	<div class="source">
				1634	<pre>{ "min_friend_count": 18, "max_friend_count": 445 }
				1635	</pre></div></div></li>
				1636	</ul></div>
				1637	<div class="section">
				1638	<h3><a name="sql-count"></a>sql-count</h3>
				1639
				1640	<ul>
				1641
				1642	<li>
				1643	<p>Syntax:</p>
				1644
				1645	<div class="source">
				1646	<div class="source">
				1647	<pre>sql-count(list)
				1648	</pre></div></div></li>
				1649
				1650	<li>
				1651	<p>Gets the number of non-null items in the given list.</p></li>
				1652
				1653	<li>Arguments:
				1654
				1655	<ul>
				1656
				1657	<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>
				1658	</ul></li>
				1659
				1660	<li>Return Value:
				1661
				1662	<ul>
				1663
				1664	<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>
				1665	</ul></li>
				1666
				1667	<li>
				1668	<p>Example:</p></li>
				1669	</ul>
				1670
				1671	<div class="source">
				1672	<div class="source">
				1673	<pre> let $l1 := ['hello', 'world', 1, 2, 3, null]
				1674	return {"count": sql-count($l1)}
				1675	</pre></div></div>
				1676
				1677	<ul>
				1678
				1679	<li>
				1680	<p>The expected result is:</p>
				1681
				1682	<div class="source">
				1683	<div class="source">
				1684	<pre>{ "count": 5i64 }
				1685	</pre></div></div></li>
				1686	</ul></div>
				1687	<div class="section">
				1688	<h3><a name="sql-avg"></a>sql-avg</h3>
				1689
				1690	<ul>
				1691
				1692	<li>
				1693	<p>Syntax:</p>
				1694
				1695	<div class="source">
				1696	<div class="source">
				1697	<pre>sql-avg(num_list)
				1698	</pre></div></div></li>
				1699
				1700	<li>
				1701	<p>Gets the average value of the non-null items in the given list.</p></li>
				1702
				1703	<li>Arguments:
				1704
				1705	<ul>
				1706
				1707	<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>
				1708	</ul></li>
				1709
				1710	<li>Return Value:
				1711
				1712	<ul>
				1713
				1714	<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>
				1715	</ul></li>
				1716
				1717	<li>
				1718	<p>Example:</p>
				1719
				1720	<div class="source">
				1721	<div class="source">
				1722	<pre>let $l := [1.2, 2.3, 3.4, 0, null]
				1723	return {"avg": sql-avg($l)}
				1724	</pre></div></div></li>
				1725
				1726	<li>
				1727	<p>The expected result is:</p>
				1728
				1729	<div class="source">
				1730	<div class="source">
				1731	<pre>{ "avg": 1.725d }
				1732	</pre></div></div></li>
				1733	</ul></div>
				1734	<div class="section">
				1735	<h3><a name="sql-sum"></a>sql-sum</h3>
				1736
				1737	<ul>
				1738
				1739	<li>
				1740	<p>Syntax:</p>
				1741
				1742	<div class="source">
				1743	<div class="source">
				1744	<pre>sql-sum(num_list)
				1745	</pre></div></div></li>
				1746
				1747	<li>
				1748	<p>Gets the sum of the non-null items in the given list.</p></li>
				1749
				1750	<li>Arguments:
				1751
				1752	<ul>
				1753
				1754	<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>
				1755	</ul></li>
				1756
				1757	<li>Return Value:
				1758
				1759	<ul>
				1760
				1761	<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>
				1762	</ul></li>
				1763
				1764	<li>
				1765	<p>Example:</p>
				1766
				1767	<div class="source">
				1768	<div class="source">
				1769	<pre>let $l := [1.2, 2.3, 3.4, 0, null]
				1770	return {"sum": sql-sum($l)}
				1771	</pre></div></div></li>
				1772
				1773	<li>
				1774	<p>The expected result is:</p>
				1775
				1776	<div class="source">
				1777	<div class="source">
				1778	<pre>{ "sum": 6.9d }
				1779	</pre></div></div></li>
				1780	</ul></div>
				1781	<div class="section">
				1782	<h3><a name="sql-minmax"></a>sql-min/max</h3>
				1783
				1784	<ul>
				1785
				1786	<li>
				1787	<p>Syntax:</p>
				1788
				1789	<div class="source">
				1790	<div class="source">
				1791	<pre>sql-min(num_list), sql-max(num_list)
				1792	</pre></div></div></li>
				1793
				1794	<li>
				1795	<p>Gets the min/max value of the non-null numeric items in the given list.</p></li>
				1796
				1797	<li>Arguments:
				1798
				1799	<ul>
				1800
				1801	<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>
				1802	</ul></li>
				1803
				1804	<li>Return Value:
				1805
				1806	<ul>
				1807
				1808	<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>
				1809	</ul></li>
				1810
				1811	<li>
				1812	<p>Example:</p>
				1813
				1814	<div class="source">
				1815	<div class="source">
				1816	<pre>let $l := [1.2, 2.3, 3.4, 0, null]
				1817	return {"min": sql-min($l), "max": sql-max($l)}
				1818	</pre></div></div></li>
				1819
				1820	<li>
				1821	<p>The expected result is:</p>
				1822
				1823	<div class="source">
				1824	<div class="source">
				1825	<pre>{ "min": 0.0d, "max": 3.4d }
				1826	</pre></div></div></li>
				1827	</ul></div></div>
				1828	<div class="section">
				1829	<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>
				1830	<div class="section">
				1831	<h3><a name="create-point"></a>create-point</h3>
				1832
				1833	<ul>
				1834
				1835	<li>
				1836	<p>Syntax:</p>
				1837
				1838	<div class="source">
				1839	<div class="source">
				1840	<pre>create-point(x, y)
				1841	</pre></div></div></li>
				1842
				1843	<li>
				1844	<p>Creates the primitive type <tt>point</tt> using an <tt>x</tt> and <tt>y</tt> value.</p></li>
				1845
				1846	<li>Arguments:</li>
				1847
				1848	<li><tt>x</tt> : A <tt>double</tt> that represents the x-coordinate.</li>
				1849
				1850	<li><tt>y</tt> : A <tt>double</tt> that represents the y-coordinate.</li>
				1851
				1852	<li>Return Value:</li>
				1853
				1854	<li>A <tt>point</tt> representing the ordered pair (<tt>x</tt>, <tt>y</tt>).</li>
				1855
				1856	<li>
				1857	<p>Example:</p>
				1858
				1859	<div class="source">
				1860	<div class="source">
				1861	<pre>use dataverse TinySocial;
				1862
				1863	let $c := create-point(30.0,70.0)
				1864	return {"point": $c}
				1865	</pre></div></div></li>
				1866	</ul>
				1867
				1868	<ul>
				1869
				1870	<li>
				1871	<p>The expected result is:</p>
				1872
				1873	<div class="source">
				1874	<div class="source">
				1875	<pre>{ "point": point("30.0,70.0") }
				1876	</pre></div></div></li>
				1877	</ul></div>
				1878	<div class="section">
				1879	<h3><a name="create-line"></a>create-line</h3>
				1880
				1881	<ul>
				1882
				1883	<li>
				1884	<p>Syntax:</p>
				1885
				1886	<div class="source">
				1887	<div class="source">
				1888	<pre>create-line(point_expression1, point_expression2)
				1889	</pre></div></div></li>
				1890
				1891	<li>
				1892	<p>Creates the primitive type <tt>line</tt> using <tt>point_expression1</tt> and <tt>point_expression2</tt>.</p></li>
				1893
				1894	<li>Arguments:
				1895
				1896	<ul>
				1897
				1898	<li><tt>point_expression1</tt> : A <tt>point</tt> that represents the start point of the line.</li>
				1899
				1900	<li><tt>point_expression2</tt> : A <tt>point</tt> that represents the end point of the line.</li>
				1901	</ul></li>
				1902
				1903	<li>Return Value:
				1904
				1905	<ul>
				1906
				1907	<li>A spatial <tt>line</tt> created using the points provided in <tt>point_expression1</tt> and <tt>point_expression2</tt>.</li>
				1908	</ul></li>
				1909
				1910	<li>
				1911	<p>Example:</p>
				1912
				1913	<div class="source">
				1914	<div class="source">
				1915	<pre>use dataverse TinySocial;
				1916
				1917	let $c := create-line(create-point(30.0,70.0), create-point(50.0,90.0))
				1918	return {"line": $c}
				1919	</pre></div></div></li>
				1920	</ul>
				1921
				1922	<ul>
				1923
				1924	<li>
				1925	<p>The expected result is:</p>
				1926
				1927	<div class="source">
				1928	<div class="source">
				1929	<pre>{ "line": line("30.0,70.0 50.0,90.0") }
				1930	</pre></div></div></li>
				1931	</ul></div>
				1932	<div class="section">
				1933	<h3><a name="create-rectangle"></a>create-rectangle</h3>
				1934
				1935	<ul>
				1936
				1937	<li>
				1938	<p>Syntax:</p>
				1939
				1940	<div class="source">
				1941	<div class="source">
				1942	<pre>create-rectangle(point_expression1, point_expression2)
				1943	</pre></div></div></li>
				1944
				1945	<li>
				1946	<p>Creates the primitive type <tt>rectangle</tt> using <tt>point_expression1</tt> and <tt>point_expression2</tt>.</p></li>
				1947
				1948	<li>Arguments:
				1949
				1950	<ul>
				1951
				1952	<li><tt>point_expression1</tt> : A <tt>point</tt> that represents the lower-left point of the rectangle.</li>
				1953
				1954	<li><tt>point_expression2</tt> : A <tt>point</tt> that represents the upper-right point of the rectangle.</li>
				1955	</ul></li>
				1956
				1957	<li>Return Value:
				1958
				1959	<ul>
				1960
				1961	<li>A spatial <tt>rectangle</tt> created using the points provided in <tt>point_expression1</tt> and <tt>point_expression2</tt>.</li>
				1962	</ul></li>
				1963
				1964	<li>
				1965	<p>Example:</p>
				1966
				1967	<div class="source">
				1968	<div class="source">
				1969	<pre>use dataverse TinySocial;
				1970
				1971	let $c := create-rectangle(create-point(30.0,70.0), create-point(50.0,90.0))
				1972	return {"rectangle": $c}
				1973	</pre></div></div></li>
				1974	</ul>
				1975
				1976	<ul>
				1977
				1978	<li>
				1979	<p>The expected result is:</p>
				1980
				1981	<div class="source">
				1982	<div class="source">
				1983	<pre>{ "rectangle": rectangle("30.0,70.0 50.0,90.0") }
				1984	</pre></div></div></li>
				1985	</ul></div>
				1986	<div class="section">
				1987	<h3><a name="create-circle"></a>create-circle</h3>
				1988
				1989	<ul>
				1990
				1991	<li>
				1992	<p>Syntax:</p>
				1993
				1994	<div class="source">
				1995	<div class="source">
				1996	<pre>create-circle(point_expression, radius)
				1997	</pre></div></div></li>
				1998
				1999	<li>
				2000	<p>Creates the primitive type <tt>circle</tt> using <tt>point_expression</tt> and <tt>radius</tt>.</p></li>
				2001
				2002	<li>Arguments:
				2003
				2004	<ul>
				2005
				2006	<li><tt>point_expression</tt> : A <tt>point</tt> that represents the center of the circle.</li>
				2007
				2008	<li><tt>radius</tt> : A <tt>double</tt> that represents the radius of the circle.</li>
				2009	</ul></li>
				2010
				2011	<li>Return Value:
				2012
				2013	<ul>
				2014
				2015	<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>
				2016	</ul></li>
				2017
				2018	<li>
				2019	<p>Example:</p>
				2020
				2021	<div class="source">
				2022	<div class="source">
				2023	<pre>use dataverse TinySocial;
				2024
				2025	let $c := create-circle(create-point(30.0,70.0), 5.0)
				2026	return {"circle": $c}
				2027	</pre></div></div></li>
				2028	</ul>
				2029
				2030	<ul>
				2031
				2032	<li>
				2033	<p>The expected result is:</p>
				2034
				2035	<div class="source">
				2036	<div class="source">
				2037	<pre>{ "circle": circle("30.0,70.0 5.0") }
				2038	</pre></div></div></li>
				2039	</ul></div>
				2040	<div class="section">
				2041	<h3><a name="create-polygon"></a>create-polygon</h3>
				2042
				2043	<ul>
				2044
				2045	<li>
				2046	<p>Syntax:</p>
				2047
				2048	<div class="source">
				2049	<div class="source">
				2050	<pre>create-polygon(list_expression)
				2051	</pre></div></div></li>
				2052
				2053	<li>
				2054	<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>
				2055
				2056	<li>Arguments:</li>
				2057
				2058	<li><tt>list_expression</tt> : An OrderedList of doubles representing the points of the polygon.</li>
				2059
				2060	<li>Return Value:</li>
				2061
				2062	<li>A <tt>polygon</tt>, represents a spatial simple polygon created using the points provided in <tt>list_expression</tt>.</li>
				2063
				2064	<li>
				2065	<p>Example:</p>
				2066
				2067	<div class="source">
				2068	<div class="source">
				2069	<pre>use dataverse TinySocial;
				2070
				2071	let $c := create-polygon([1.0,1.0,2.0,2.0,3.0,3.0,4.0,4.0])
				2072	return {"polygon": $c}
				2073	</pre></div></div></li>
				2074	</ul>
				2075
				2076	<ul>
				2077
				2078	<li>
				2079	<p>The expected result is:</p>
				2080
				2081	<div class="source">
				2082	<div class="source">
				2083	<pre>{ "polygon": polygon("1.0,1.0 2.0,2.0 3.0,3.0 4.0,4.0") }
				2084	</pre></div></div></li>
				2085	</ul></div>
				2086	<div class="section">
				2087	<h3><a name="get-xget-y"></a>get-x/get-y</h3>
				2088
				2089	<ul>
				2090
				2091	<li>
				2092	<p>Syntax:</p>
				2093
				2094	<div class="source">
				2095	<div class="source">
				2096	<pre>get-x(point_expression) or get-y(point_expression)
				2097	</pre></div></div></li>
				2098
				2099	<li>
				2100	<p>Returns the x or y coordinates of a point <tt>point_expression</tt>.</p></li>
				2101
				2102	<li>Arguments:
				2103
				2104	<ul>
				2105
				2106	<li><tt>point_expression</tt> : A <tt>point</tt>.</li>
				2107	</ul></li>
				2108
				2109	<li>Return Value:
				2110
				2111	<ul>
				2112
				2113	<li>A <tt>double</tt> representing the x or y coordinates of the point <tt>point_expression</tt>.</li>
				2114	</ul></li>
				2115
				2116	<li>
				2117	<p>Example:</p>
				2118
				2119	<div class="source">
				2120	<div class="source">
				2121	<pre>use dataverse TinySocial;
				2122
				2123	let $point := create-point(2.3,5.0)
				2124	return {"x-coordinate": get-x($point), "y-coordinate": get-y($point)}
				2125	</pre></div></div></li>
				2126	</ul>
				2127
				2128	<ul>
				2129
				2130	<li>
				2131	<p>The expected result is:</p>
				2132
				2133	<div class="source">
				2134	<div class="source">
				2135	<pre>{ "x-coordinate": 2.3d, "y-coordinate": 5.0d }
				2136	</pre></div></div></li>
				2137	</ul></div>
				2138	<div class="section">
				2139	<h3><a name="get-points"></a>get-points</h3>
				2140
				2141	<ul>
				2142
				2143	<li>
				2144	<p>Syntax:</p>
				2145
				2146	<div class="source">
				2147	<div class="source">
				2148	<pre>get-points(spatial_expression)
				2149	</pre></div></div></li>
				2150
				2151	<li>
				2152	<p>Returns an ordered list of the points forming the spatial object <tt>spatial_expression</tt>.</p></li>
				2153
				2154	<li>Arguments:
				2155
				2156	<ul>
				2157
				2158	<li><tt>spatial_expression</tt> : A <tt>point</tt>, <tt>line</tt>, <tt>rectangle</tt>, <tt>circle</tt>, or <tt>polygon</tt>.</li>
				2159	</ul></li>
				2160
				2161	<li>Return Value:
				2162
				2163	<ul>
				2164
				2165	<li>An <tt>OrderedList</tt> of the points forming the spatial object <tt>spatial_expression</tt>.</li>
				2166	</ul></li>
				2167
				2168	<li>
				2169	<p>Example:</p>
				2170
				2171	<div class="source">
				2172	<div class="source">
				2173	<pre>use dataverse TinySocial;
				2174
				2175	let $line := create-line(create-point(100.6,99.4), create-point(-72.0,-76.9))
				2176	let $rectangle := create-rectangle(create-point(9.2,49.0), create-point(77.8,111.1))
				2177	let $polygon := create-polygon([1.0,1.0,2.0,2.0,3.0,3.0,4.0,4.0])
				2178	let $line_list := get-points($line)
				2179	let $rectangle_list := get-points($rectangle)
				2180	let $polygon_list := get-points($polygon)
				2181	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]}
				2182	</pre></div></div></li>
				2183	</ul>
				2184
				2185	<ul>
				2186
				2187	<li>
				2188	<p>The expected result is:</p>
				2189
				2190	<div class="source">
				2191	<div class="source">
				2192	<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") }
				2193	</pre></div></div></li>
				2194	</ul></div>
				2195	<div class="section">
				2196	<h3><a name="get-centerget-radius"></a>get-center/get-radius</h3>
				2197
				2198	<ul>
				2199
				2200	<li>
				2201	<p>Syntax:</p>
				2202
				2203	<div class="source">
				2204	<div class="source">
				2205	<pre>get-center(circle_expression) or get-radius(circle_expression)
				2206	</pre></div></div></li>
				2207
				2208	<li>
				2209	<p>Returns the center and the radius of a circle <tt>circle_expression</tt>, respectively.</p></li>
				2210
				2211	<li>Arguments:
				2212
				2213	<ul>
				2214
				2215	<li><tt>circle_expression</tt> : A <tt>circle</tt>.</li>
				2216	</ul></li>
				2217
				2218	<li>Return Value:
				2219
				2220	<ul>
				2221
				2222	<li>A <tt>point</tt> or <tt>double</tt>, represent the center or radius of the circle <tt>circle_expression</tt>.</li>
				2223	</ul></li>
				2224
				2225	<li>
				2226	<p>Example:</p>
				2227
				2228	<div class="source">
				2229	<div class="source">
				2230	<pre>use dataverse TinySocial;
				2231
				2232	let $circle := create-circle(create-point(6.0,3.0), 1.0)
				2233	return {"circle-radius": get-radius($circle), "circle-center": get-center($circle)}
				2234	</pre></div></div></li>
				2235	</ul>
				2236
				2237	<ul>
				2238
				2239	<li>
				2240	<p>The expected result is:</p>
				2241
				2242	<div class="source">
				2243	<div class="source">
				2244	<pre>{ "circle-radius": 1.0d, "circle-center": point("6.0,3.0") }
				2245	</pre></div></div></li>
				2246	</ul></div>
				2247	<div class="section">
				2248	<h3><a name="spatial-distance"></a>spatial-distance</h3>
				2249
				2250	<ul>
				2251
				2252	<li>
				2253	<p>Syntax:</p>
				2254
				2255	<div class="source">
				2256	<div class="source">
				2257	<pre>spatial-distance(point_expression1, point_expression2)
				2258	</pre></div></div></li>
				2259
				2260	<li>
				2261	<p>Returns the Euclidean distance between <tt>point_expression1</tt> and <tt>point_expression2</tt>.</p></li>
				2262
				2263	<li>Arguments:
				2264
				2265	<ul>
				2266
				2267	<li><tt>point_expression1</tt> : A <tt>point</tt>.</li>
				2268
				2269	<li><tt>point_expression2</tt> : A <tt>point</tt>.</li>
				2270	</ul></li>
				2271
				2272	<li>Return Value:
				2273
				2274	<ul>
				2275
				2276	<li>A <tt>double</tt> as the Euclidean distance between <tt>point_expression1</tt> and <tt>point_expression2</tt>.</li>
				2277	</ul></li>
				2278
				2279	<li>
				2280	<p>Example:</p>
				2281
				2282	<div class="source">
				2283	<div class="source">
				2284	<pre>use dataverse TinySocial;
				2285
				2286	for $t in dataset('TweetMessages')
				2287	let $d := spatial-distance($t.sender-location, create-point(30.0,70.0))
				2288	return {"point": $t.sender-location, "distance": $d}
				2289	</pre></div></div></li>
				2290	</ul>
				2291
				2292	<ul>
				2293
				2294	<li>
				2295	<p>The expected result is:</p>
				2296
				2297	<div class="source">
				2298	<div class="source">
				2299	<pre>{ "point": point("47.44,80.65"), "distance": 20.434678857275934d }
				2300	{ "point": point("29.15,76.53"), "distance": 6.585089217315132d }
				2301	{ "point": point("37.59,68.42"), "distance": 7.752709203884797d }
				2302	{ "point": point("24.82,94.63"), "distance": 25.168816023007512d }
				2303	{ "point": point("32.84,67.14"), "distance": 4.030533463451212d }
				2304	{ "point": point("29.72,75.8"), "distance": 5.806754687430835d }
				2305	{ "point": point("39.28,70.48"), "distance": 9.292405501268227d }
				2306	{ "point": point("40.09,92.69"), "distance": 24.832321679617472d }
				2307	{ "point": point("47.51,83.99"), "distance": 22.41250097601782d }
				2308	{ "point": point("36.21,72.6"), "distance": 6.73231758015024d }
				2309	{ "point": point("46.05,93.34"), "distance": 28.325926286707734d }
				2310	{ "point": point("36.86,74.62"), "distance": 8.270671073135482d }
				2311	</pre></div></div></li>
				2312	</ul></div>
				2313	<div class="section">
				2314	<h3><a name="spatial-area"></a>spatial-area</h3>
				2315
				2316	<ul>
				2317
				2318	<li>
				2319	<p>Syntax:</p>
				2320
				2321	<div class="source">
				2322	<div class="source">
				2323	<pre>spatial-area(spatial_2d_expression)
				2324	</pre></div></div></li>
				2325
				2326	<li>
				2327	<p>Returns the spatial area of <tt>spatial_2d_expression</tt>.</p></li>
				2328
				2329	<li>Arguments:
				2330
				2331	<ul>
				2332
				2333	<li><tt>spatial_2d_expression</tt> : A <tt>rectangle</tt>, <tt>circle</tt>, or <tt>polygon</tt>.</li>
				2334	</ul></li>
				2335
				2336	<li>Return Value:
				2337
				2338	<ul>
				2339
				2340	<li>A <tt>double</tt> representing the area of <tt>spatial_2d_expression</tt>.</li>
				2341	</ul></li>
				2342
				2343	<li>
				2344	<p>Example:</p>
				2345
				2346	<div class="source">
				2347	<div class="source">
				2348	<pre>use dataverse TinySocial;
				2349
				2350	let $circleArea := spatial-area(create-circle(create-point(0.0,0.0), 5.0))
				2351	return {"Area":$circleArea}
				2352	</pre></div></div></li>
				2353	</ul>
				2354
				2355	<ul>
				2356
				2357	<li>
				2358	<p>The expected result is:</p>
				2359
				2360	<div class="source">
				2361	<div class="source">
				2362	<pre>{ "Area": 78.53981625d }
				2363	</pre></div></div></li>
				2364	</ul></div>
				2365	<div class="section">
				2366	<h3><a name="spatial-intersect"></a>spatial-intersect</h3>
				2367
				2368	<ul>
				2369
				2370	<li>
				2371	<p>Syntax:</p>
				2372
				2373	<div class="source">
				2374	<div class="source">
				2375	<pre>spatial-intersect(spatial_expression1, spatial_expression2)
				2376	</pre></div></div></li>
				2377
				2378	<li>
				2379	<p>Checks whether <tt>@arg1</tt> and <tt>@arg2</tt> spatially intersect each other.</p></li>
				2380
				2381	<li>Arguments:
				2382
				2383	<ul>
				2384
				2385	<li><tt>spatial_expression1</tt> : A <tt>point</tt>, <tt>line</tt>, <tt>rectangle</tt>, <tt>circle</tt>, or <tt>polygon</tt>.</li>
				2386
				2387	<li><tt>spatial_expression2</tt> : A <tt>point</tt>, <tt>line</tt>, <tt>rectangle</tt>, <tt>circle</tt>, or <tt>polygon</tt>.</li>
				2388	</ul></li>
				2389
				2390	<li>Return Value:
				2391
				2392	<ul>
				2393
				2394	<li>A <tt>boolean</tt> representing whether <tt>spatial_expression1</tt> and <tt>spatial_expression2</tt> spatially overlap with each other.</li>
				2395	</ul></li>
				2396
				2397	<li>
				2398	<p>Example:</p>
				2399
				2400	<div class="source">
				2401	<div class="source">
				2402	<pre>use dataverse TinySocial;
				2403
				2404	for $t in dataset('TweetMessages')
				2405	where spatial-intersect($t.sender-location, create-rectangle(create-point(30.0,70.0), create-point(40.0,80.0)))
				2406	return $t
				2407	</pre></div></div></li>
				2408	</ul>
				2409
				2410	<ul>
				2411
				2412	<li>
				2413	<p>The expected result is:</p>
				2414
				2415	<div class="source">
				2416	<div class="source">
				2417	<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:)" }
				2418	{ "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" }
				2419	{ "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" }
				2420	</pre></div></div></li>
				2421	</ul></div>
				2422	<div class="section">
				2423	<h3><a name="spatial-cell"></a>spatial-cell</h3>
				2424
				2425	<ul>
				2426
				2427	<li>
				2428	<p>Syntax:</p>
				2429
				2430	<div class="source">
				2431	<div class="source">
				2432	<pre>spatial-cell(point_expression1, point_expression2, x_increment, y_increment)
				2433	</pre></div></div></li>
				2434
				2435	<li>
				2436	<p>Returns the grid cell that <tt>point_expression1</tt> belongs to.</p></li>
				2437
				2438	<li>Arguments:
				2439
				2440	<ul>
				2441
				2442	<li><tt>point_expression1</tt> : A <tt>point</tt> representing the point of interest that its grid cell will be returned.</li>
				2443
				2444	<li><tt>point_expression2</tt> : A <tt>point</tt> representing the origin of the grid.</li>
				2445
				2446	<li><tt>x_increment</tt> : A <tt>double</tt>, represents X increments.</li>
				2447
				2448	<li><tt>y_increment</tt> : A <tt>double</tt>, represents Y increments.</li>
				2449	</ul></li>
				2450
				2451	<li>Return Value:
				2452
				2453	<ul>
				2454
				2455	<li>A <tt>rectangle</tt> representing the grid cell that <tt>point_expression1</tt> belongs to.</li>
				2456	</ul></li>
				2457
				2458	<li>
				2459	<p>Example:</p>
				2460
				2461	<div class="source">
				2462	<div class="source">
				2463	<pre>use dataverse TinySocial;
				2464
				2465	for $t in dataset('TweetMessages')
				2466	group by $c := spatial-cell($t.sender-location, create-point(20.0,50.0), 5.5, 6.0) with $t
				2467	let $num := count($t)
				2468	return { "cell": $c, "count": $num}
				2469	</pre></div></div></li>
				2470	</ul>
				2471
				2472	<ul>
				2473
				2474	<li>
				2475	<p>The expected result is:</p>
				2476
				2477	<div class="source">
				2478	<div class="source">
				2479	<pre>{ "cell": rectangle("20.0,92.0 25.5,98.0"), "count": 1i64 }
				2480	{ "cell": rectangle("25.5,74.0 31.0,80.0"), "count": 2i64 }
				2481	{ "cell": rectangle("31.0,62.0 36.5,68.0"), "count": 1i64 }
				2482	{ "cell": rectangle("31.0,68.0 36.5,74.0"), "count": 1i64 }
				2483	{ "cell": rectangle("36.5,68.0 42.0,74.0"), "count": 2i64 }
				2484	{ "cell": rectangle("36.5,74.0 42.0,80.0"), "count": 1i64 }
				2485	{ "cell": rectangle("36.5,92.0 42.0,98.0"), "count": 1i64 }
				2486	{ "cell": rectangle("42.0,80.0 47.5,86.0"), "count": 1i64 }
				2487	{ "cell": rectangle("42.0,92.0 47.5,98.0"), "count": 1i64 }
				2488	{ "cell": rectangle("47.5,80.0 53.0,86.0"), "count": 1i64 }
				2489	</pre></div></div></li>
				2490	</ul></div></div>
				2491	<div class="section">
				2492	<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>
				2493	<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>
				2494	<div class="section">
				2495	<h3><a name="edit-distance"></a>edit-distance</h3>
				2496
				2497	<ul>
				2498
				2499	<li>
				2500	<p>Syntax:</p>
				2501
				2502	<div class="source">
				2503	<div class="source">
				2504	<pre>edit-distance(expression1, expression2)
				2505	</pre></div></div></li>
				2506
				2507	<li>
				2508	<p>Returns the edit distance of <tt>expression1</tt> and <tt>expression2</tt>.</p></li>
				2509
				2510	<li>Arguments:
				2511
				2512	<ul>
				2513
				2514	<li><tt>expression1</tt> : A <tt>string</tt> or a homogeneous <tt>OrderedList</tt> of a comparable item type.</li>
				2515
				2516	<li><tt>expression2</tt> : The same type as <tt>expression1</tt>.</li>
				2517	</ul></li>
				2518
				2519	<li>Return Value:
				2520
				2521	<ul>
				2522
				2523	<li>An <tt>int64</tt> that represents the edit distance between <tt>expression1</tt> and <tt>expression2</tt>.</li>
				2524	</ul></li>
				2525
				2526	<li>Note: An <a href="similarity.html#UsingIndexesToSupportSimilarityQueries">n-gram index</a> can be utilized for this function.</li>
				2527
				2528	<li>
				2529	<p>Example:</p>
				2530
				2531	<div class="source">
				2532	<div class="source">
				2533	<pre>use dataverse TinySocial;
				2534
				2535	for $user in dataset('FacebookUsers')
				2536	let $ed := edit-distance($user.name, "Suzanna Tilson")
				2537	where $ed <= 2
				2538	return $user
				2539	</pre></div></div></li>
				2540	</ul>
				2541
				2542	<ul>
				2543
				2544	<li>
				2545	<p>The expected result is:</p>
				2546
				2547	<div class="source">
				2548	<div class="source">
				2549	<pre>{
				2550	"id": 7, "alias": "Suzanna", "name": "SuzannaTillson", "user-since": datetime("2012-08-07T10:10:00.000Z"), "friend-ids": {{ 6 }},
				2551	"employment": [ { "organization-name": "Labzatron", "start-date": date("2011-04-19"), "end-date": null } ]
				2552	}
				2553	</pre></div></div></li>
				2554	</ul></div>
				2555	<div class="section">
				2556	<h3><a name="edit-distance-check"></a>edit-distance-check</h3>
				2557
				2558	<ul>
				2559
				2560	<li>
				2561	<p>Syntax:</p>
				2562
				2563	<div class="source">
				2564	<div class="source">
				2565	<pre>edit-distance-check(expression1, expression2, threshold)
				2566	</pre></div></div></li>
				2567
				2568	<li>
				2569	<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>
				2570
				2571	<li>
				2572	<p>Arguments:</p>
				2573
				2574	<ul>
				2575
				2576	<li><tt>expression1</tt> : A <tt>string</tt> or a homogeneous <tt>OrderedList</tt> of a comparable item type.</li>
				2577
				2578	<li><tt>expression2</tt> : The same type as <tt>expression1</tt>.</li>
				2579
				2580	<li><tt>threshold</tt> : An <tt>int64</tt> that represents the distance threshold.</li>
				2581	</ul></li>
				2582
				2583	<li>Return Value:
				2584
				2585	<ul>
				2586
				2587	<li>An <tt>OrderedList</tt> with two items:
				2588
				2589	<ul>
				2590
				2591	<li>The first item contains a <tt>boolean</tt> value representing whether <tt>expression1</tt> and <tt>expression2</tt> are similar.</li>
				2592
				2593	<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>
				2594	</ul></li>
				2595	</ul></li>
				2596
				2597	<li>Note: An <a href="similarity.html#UsingIndexesToSupportSimilarityQueries">n-gram index</a> can be utilized for this function.</li>
				2598
				2599	<li>
				2600	<p>Example:</p>
				2601
				2602	<div class="source">
				2603	<div class="source">
				2604	<pre>use dataverse TinySocial;
				2605
				2606	for $user in dataset('FacebookUsers')
				2607	let $ed := edit-distance-check($user.name, "Suzanna Tilson", 2)
				2608	where $ed[0]
				2609	return $ed[1]
				2610	</pre></div></div></li>
				2611	</ul>
				2612
				2613	<ul>
				2614
				2615	<li>
				2616	<p>The expected result is:</p>
				2617
				2618	<div class="source">
				2619	<div class="source">
				2620	<pre>2
				2621	</pre></div></div></li>
				2622	</ul></div>
				2623	<div class="section">
				2624	<h3><a name="edit-distance-contains"></a>edit-distance-contains</h3>
				2625
				2626	<ul>
				2627
				2628	<li>Syntax:</li>
				2629	</ul>
				2630	<p>edit-distance-contains(expression1, expression2, threshold)</p>
				2631
				2632	<ul>
				2633
				2634	<li>
				2635	<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>
				2636
				2637	<li>
				2638	<p>Arguments:</p>
				2639
				2640	<ul>
				2641
				2642	<li><tt>expression1</tt> : A <tt>string</tt> or a homogeneous <tt>OrderedList</tt> of a comparable item type.</li>
				2643
				2644	<li><tt>expression2</tt> : The same type as <tt>expression1</tt>.</li>
				2645
				2646	<li><tt>threshold</tt> : An <tt>int32</tt> that represents the distance threshold.</li>
				2647	</ul></li>
				2648
				2649	<li>Return Value:
				2650
				2651	<ul>
				2652
				2653	<li>An <tt>OrderedList</tt> with two items:
				2654
				2655	<ul>
				2656
				2657	<li>The first item contains a <tt>boolean</tt> value representing whether <tt>expression1</tt> can contain <tt>expression2</tt>.</li>
				2658
				2659	<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>
				2660	</ul></li>
				2661	</ul></li>
				2662
				2663	<li>Note: An <a href="similarity.html#UsingIndexesToSupportSimilarityQueries">n-gram index</a> can be utilized for this function.</li>
				2664
				2665	<li>
				2666	<p>Example:</p>
				2667
				2668	<div class="source">
				2669	<div class="source">
				2670	<pre>let $i := edit-distance-contains("happy","hapr",2)
				2671	return $i;
				2672	</pre></div></div></li>
				2673	</ul>
				2674
				2675	<ul>
				2676
				2677	<li>
				2678	<p>The expected result is:</p>
				2679
				2680	<div class="source">
				2681	<div class="source">
				2682	<pre>[ true, 1 ]
				2683	</pre></div></div></li>
				2684	</ul></div>
				2685	<div class="section">
				2686	<h3><a name="similarity-jaccard"></a>similarity-jaccard</h3>
				2687
				2688	<ul>
				2689
				2690	<li>
				2691	<p>Syntax:</p>
				2692
				2693	<div class="source">
				2694	<div class="source">
				2695	<pre>similarity-jaccard(list_expression1, list_expression2)
				2696	</pre></div></div></li>
				2697
				2698	<li>
				2699	<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>
				2700
				2701	<li>Arguments:
				2702
				2703	<ul>
				2704
				2705	<li><tt>list_expression1</tt> : An <tt>UnorderedList</tt> or <tt>OrderedList</tt>.</li>
				2706
				2707	<li><tt>list_expression2</tt> : An <tt>UnorderedList</tt> or <tt>OrderedList</tt>.</li>
				2708	</ul></li>
				2709
				2710	<li>Return Value:
				2711
				2712	<ul>
				2713
				2714	<li>A <tt>float</tt> that represents the Jaccard similarity of <tt>list_expression1</tt> and <tt>list_expression2</tt>.</li>
				2715	</ul></li>
				2716
				2717	<li>Note: A <a href="similarity.html#UsingIndexesToSupportSimilarityQueries">keyword index</a> can be utilized for this function.</li>
				2718
				2719	<li>
				2720	<p>Example:</p>
				2721
				2722	<div class="source">
				2723	<div class="source">
				2724	<pre>use dataverse TinySocial;
				2725
				2726	for $user in dataset('FacebookUsers')
				2727	let $sim := similarity-jaccard($user.friend-ids, [1,5,9,10])
				2728	where $sim >= 0.6f
				2729	return $user
				2730	</pre></div></div></li>
				2731	</ul>
				2732
				2733	<ul>
				2734
				2735	<li>
				2736	<p>The expected result is:</p>
				2737
				2738	<div class="source">
				2739	<div class="source">
				2740	<pre>{
				2741	"id": 3, "alias": "Emory", "name": "EmoryUnk", "user-since": datetime("2012-07-10T10:10:00.000Z"), "friend-ids": {{ 1, 5, 8, 9 }},
				2742	"employment": [ { "organization-name": "geomedia", "start-date": date("2010-06-17"), "end-date": date("2010-01-26") } ]
				2743	}
				2744	{
				2745	"id": 10, "alias": "Bram", "name": "BramHatch", "user-since": datetime("2010-10-16T10:10:00.000Z"), "friend-ids": {{ 1, 5, 9 }},
				2746	"employment": [ { "organization-name": "physcane", "start-date": date("2007-06-05"), "end-date": date("2011-11-05") } ]
				2747	}
				2748	</pre></div></div></li>
				2749	</ul></div>
				2750	<div class="section">
				2751	<h3><a name="similarity-jaccard-check"></a>similarity-jaccard-check</h3>
				2752
				2753	<ul>
				2754
				2755	<li>
				2756	<p>Syntax:</p>
				2757
				2758	<div class="source">
				2759	<div class="source">
				2760	<pre>similarity-jaccard-check(list_expression1, list_expression2, threshold)
				2761	</pre></div></div></li>
				2762
				2763	<li>
				2764	<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>
				2765
				2766	<li>
				2767	<p>Arguments:</p>
				2768
				2769	<ul>
				2770
				2771	<li><tt>list_expression1</tt> : An <tt>UnorderedList</tt> or <tt>OrderedList</tt>.</li>
				2772
				2773	<li><tt>list_expression2</tt> : An <tt>UnorderedList</tt> or <tt>OrderedList</tt>.</li>
				2774
				2775	<li><tt>threshold</tt> : A <tt>float</tt> that represents the similarity threshold.</li>
				2776	</ul></li>
				2777
				2778	<li>Return Value:
				2779
				2780	<ul>
				2781
				2782	<li>An <tt>OrderedList</tt> with two items:</li>
				2783
				2784	<li>The first item contains a <tt>boolean</tt> value representing whether <tt>list_expression1</tt> and <tt>list_expression2</tt> are similar.</li>
				2785
				2786	<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>
				2787	</ul></li>
				2788
				2789	<li>Note: A <a href="similarity.html#UsingIndexesToSupportSimilarityQueries">keyword index</a> can be utilized for this function.</li>
				2790
				2791	<li>
				2792	<p>Example:</p>
				2793
				2794	<div class="source">
				2795	<div class="source">
				2796	<pre>use dataverse TinySocial;
				2797
				2798	for $user in dataset('FacebookUsers')
				2799	let $sim := similarity-jaccard-check($user.friend-ids, [1,5,9,10], 0.6f)
				2800	where $sim[0]
				2801	return $sim[1]
				2802	</pre></div></div></li>
				2803	</ul>
				2804
				2805	<ul>
				2806
				2807	<li>
				2808	<p>The expected result is:</p>
				2809
				2810	<div class="source">
				2811	<div class="source">
				2812	<pre>0.75f
				2813	1.0f
				2814	</pre></div></div></li>
				2815	</ul></div>
				2816	<div class="section">
				2817	<h3><a name="Similarity_Operator_"></a>Similarity Operator ~=</h3>
				2818
				2819	<ul>
				2820
				2821	<li>“<tt>~=</tt>” is syntactic sugar for expressing a similarity condition with a given similarity threshold.</li>
				2822
				2823	<li>The similarity function and threshold for “<tt>~=</tt>” are controlled via “set” directives.</li>
				2824
				2825	<li>The “<tt>~=</tt>” operator returns a <tt>boolean</tt> value that represents whether the operands are similar.</li>
				2826
				2827	<li>
				2828	<p>Example for Jaccard similarity:</p>
				2829
				2830	<div class="source">
				2831	<div class="source">
				2832	<pre>use dataverse TinySocial;
				2833
				2834	set simfunction "jaccard";
				2835	set simthreshold "0.6f";
				2836
				2837	for $user in dataset('FacebookUsers')
				2838	where $user.friend-ids ~= [1,5,9,10]
				2839	return $user
				2840	</pre></div></div></li>
				2841	</ul>
				2842
				2843	<ul>
				2844
				2845	<li>
				2846	<p>The expected result is:</p>
				2847
				2848	<div class="source">
				2849	<div class="source">
				2850	<pre>{
				2851	"id": 3, "alias": "Emory", "name": "EmoryUnk", "user-since": datetime("2012-07-10T10:10:00.000Z"), "friend-ids": {{ 1, 5, 8, 9 }},
				2852	"employment": [ { "organization-name": "geomedia", "start-date": date("2010-06-17"), "end-date": date("2010-01-26") } ]
				2853	}
				2854	{
				2855	"id": 10, "alias": "Bram", "name": "BramHatch", "user-since": datetime("2010-10-16T10:10:00.000Z"), "friend-ids": {{ 1, 5, 9 }},
				2856	"employment": [ { "organization-name": "physcane", "start-date": date("2007-06-05"), "end-date": date("2011-11-05") } ]
				2857	}
				2858	</pre></div></div></li>
				2859	</ul>
				2860
				2861	<ul>
				2862
				2863	<li>
				2864	<p>Example for edit-distance similarity:</p>
				2865
				2866	<div class="source">
				2867	<div class="source">
				2868	<pre>use dataverse TinySocial;
				2869
				2870	set simfunction "edit-distance";
				2871	set simthreshold "2";
				2872
				2873	for $user in dataset('FacebookUsers')
				2874	where $user.name ~= "Suzanna Tilson"
				2875	return $user
				2876	</pre></div></div></li>
				2877	</ul>
				2878
				2879	<ul>
				2880
				2881	<li>
				2882	<p>The expected output is:</p>
				2883
				2884	<div class="source">
				2885	<div class="source">
				2886	<pre>{
				2887	"id": 7, "alias": "Suzanna", "name": "SuzannaTillson", "user-since": datetime("2012-08-07T10:10:00.000Z"), "friend-ids": {{ 6 }},
				2888	"employment": [ { "organization-name": "Labzatron", "start-date": date("2011-04-19"), "end-date": null } ]
				2889	}
				2890	</pre></div></div></li>
				2891	</ul></div></div>
				2892	<div class="section">
				2893	<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>
				2894	<div class="section">
				2895	<h3><a name="word-tokens"></a>word-tokens</h3>
				2896
				2897	<ul>
				2898
				2899	<li>
				2900	<p>Syntax:</p>
				2901
				2902	<div class="source">
				2903	<div class="source">
				2904	<pre>word-tokens(string_expression)
				2905	</pre></div></div></li>
				2906
				2907	<li>
				2908	<p>Returns a list of word tokens of <tt>string_expression</tt> using non-alphanumeric characters as delimiters.</p></li>
				2909
				2910	<li>Arguments:
				2911
				2912	<ul>
				2913
				2914	<li><tt>string_expression</tt> : A <tt>string</tt> that will be tokenized.</li>
				2915	</ul></li>
				2916
				2917	<li>Return Value:
				2918
				2919	<ul>
				2920
				2921	<li>An <tt>OrderedList</tt> of <tt>string</tt> word tokens.</li>
				2922	</ul></li>
				2923
				2924	<li>
				2925	<p>Example:</p>
				2926
				2927	<div class="source">
				2928	<div class="source">
				2929	<pre>use dataverse TinySocial;
				2930
				2931	for $t in dataset('TweetMessages')
				2932	let $tokens := word-tokens($t.message-text)
				2933	where $t.send-time >= datetime('2012-01-01T00:00:00')
				2934	return {
				2935	"tweetid": $t.tweetid,
				2936	"word-tokens": $tokens
				2937	}
				2938	</pre></div></div></li>
				2939	</ul>
				2940
				2941	<ul>
				2942
				2943	<li>
				2944	<p>The expected result is:</p>
				2945
				2946	<div class="source">
				2947	<div class="source">
				2948	<pre>{ "tweetid": "9", "word-tokens": [ "love", "verizon", "its", "voicemail", "service", "is", "awesome" ] }
				2949	</pre></div></div></li>
				2950	</ul>
				2951	<!-- ### hashed-word-tokens ###
				2952	* Syntax:
				2953
				2954	hashed-word-tokens(string_expression)
				2955
				2956	* Returns a list of hashed word tokens of `string_expression`.
				2957	* Arguments:
				2958	* `string_expression` : A `string` that will be tokenized.
				2959	* Return Value:
				2960	* An `OrderedList` of `int32` hashed tokens.
				2961
				2962	* Example:
				2963
				2964	use dataverse TinySocial;
				2965
				2966	for $t in dataset('TweetMessages')
				2967	let $tokens := hashed-word-tokens($t.message-text)
				2968	where $t.send-time >= datetime('2012-01-01T00:00:00')
				2969	return {
				2970	"tweetid": $t.tweetid,
				2971	"hashed-word-tokens": $tokens
				2972	}
				2973
				2974
				2975	* The expected result is:
				2976
				2977	{ "tweetid": "9", "hashed-word-tokens": [ -1217719622, -447857469, -1884722688, -325178649, 210976949, 285049676, 1916743959 ] }
				2978
				2979
				2980	### counthashed-word-tokens ###
				2981	* Syntax:
				2982
				2983	counthashed-word-tokens(string_expression)
				2984
				2985	* 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.
				2986	* Arguments:
				2987	* `string_expression` : A `String` that will be tokenized.
				2988	* Return Value:
				2989	* An `OrderedList` of `Int32` hashed tokens.
				2990	* Example:
				2991
				2992	use dataverse TinySocial;
				2993
				2994	for $t in dataset('TweetMessages')
				2995	let $tokens := counthashed-word-tokens($t.message-text)
				2996	where $t.send-time >= datetime('2012-01-01T00:00:00')
				2997	return {
				2998	"tweetid": $t.tweetid,
				2999	"counthashed-word-tokens": $tokens
				3000	}
				3001
				3002
				3003	* The expected result is:
				3004
				3005	{ "tweetid": "9", "counthashed-word-tokens": [ -1217719622, -447857469, -1884722688, -325178649, 210976949, 285049676, 1916743959 ] }
				3006
				3007
				3008	### gram-tokens ###
				3009	* Syntax:
				3010
				3011	gram-tokens(string_expression, gram_length, boolean_expression)
				3012
				3013	* 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.
				3014	* Arguments:
				3015	* `string_expression` : A `String` that will be tokenized.
				3016	* `gram_length` : An `Int32` as the length of grams.
				3017	* `boolean_expression` : A `Boolean` value to indicate whether to generate additional grams by pre- and postfixing `string_expression` with special characters.
				3018	* Return Value:
				3019	* An `OrderedList` of String gram tokens.
				3020
				3021	* Example:
				3022
				3023	use dataverse TinySocial;
				3024
				3025	for $t in dataset('TweetMessages')
				3026	let $tokens := gram-tokens($t.message-text, 3, true)
				3027	where $t.send-time >= datetime('2012-01-01T00:00:00')
				3028	return {
				3029	"tweetid": $t.tweetid,
				3030	"gram-tokens": $tokens
				3031	}
				3032
				3033
				3034	* The expected result is:
				3035
				3036	{
				3037	"tweetid": "9",
				3038	"gram-tokens": [ "## ", "# l", " lo", "lov", "ove", "ve ", "e v", " ve", "ver", "eri", "riz", "izo", "zon", "on ", "n i", " it", "its", "ts ", "s v", " vo", "voi", "oic", "ice",
				3039	"cem", "ema", "mai", "ail", "il-", "l-s", "-se", "ser", "erv", "rvi", "vic", "ice", "ce ", "e i", " is", "is ", "s a", " aw", "awe", "wes", "eso", "som", "ome", "me$", "e$$" ]
				3040	}
				3041
				3042
				3043	### hashed-gram-tokens ###
				3044	* Syntax:
				3045
				3046	hashed-gram-tokens(string_expression, gram_length, boolean_expression)
				3047
				3048	* Returns a list of hashed gram tokens of `string_expression`.
				3049	* Arguments:
				3050	* `string_expression` : A `String` that will be tokenized.
				3051	* `gram_length` : An `Int32` as the length of grams.
				3052	* `boolean_expression` : A `Boolean` to indicate whether to generate additional grams by pre- and postfixing `string_expression` with special characters.
				3053	* Return Value:
				3054	* An `OrderedList` of `Int32` hashed gram tokens.
				3055
				3056	* Example:
				3057
				3058	use dataverse TinySocial;
				3059
				3060	for $t in dataset('TweetMessages')
				3061	let $tokens := hashed-gram-tokens($t.message-text, 3, true)
				3062	where $t.send-time >= datetime('2012-01-01T00:00:00')
				3063	return {
				3064	"tweetid": $t.tweetid,
				3065	"hashed-gram-tokens": $tokens
				3066	}
				3067
				3068
				3069	* The expected result is:
				3070
				3071	{
				3072	"tweetid": "9",
				3073	"hashed-gram-tokens": [ 40557178, -2002241593, 161665899, -856104603, -500544946, 693410611, 395674299, -1015235909, 1115608337, 1187999872, -31006095, -219180466, -1676061637,
				3074	1040194153, -1339307841, -1527110163, -1884722688, -179148713, -431014627, -1789789823, -1209719926, 684519765, -486734513, 1734740619, -1971673751, -932421915, -2064668066,
				3075	-937135958, -790946468, -69070309, 1561601454, 26169001, -160734571, 1330043462, -486734513, -18796768, -470303314, 113421364, 1615760212, 1688217556, 1223719184, 536568131,
				3076	1682609873, 2935161, -414769471, -1027490137, 1602276102, 1050490461 ]
				3077	}
				3078
				3079
				3080	### counthashed-gram-tokens ###
				3081	* Syntax:
				3082
				3083	counthashed-gram-tokens(string_expression, gram_length, boolean_expression)
				3084
				3085	* 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.
				3086	* Arguments:
				3087	* `string_expression` : A `String` that will be tokenized.
				3088	* `gram_length` : An `Int32`, length of grams to generate.
				3089	* `boolean_expression` : A `Boolean`, whether to generate additional grams by pre- and postfixing `string_expression` with special characters.
				3090	* Return Value:
				3091	* An `OrderedList` of `Int32` hashed gram tokens.
				3092
				3093	* Example:
				3094
				3095	use dataverse TinySocial;
				3096
				3097	for $t in dataset('TweetMessages')
				3098	let $tokens := counthashed-gram-tokens($t.message-text, 3, true)
				3099	where $t.send-time >= datetime('2012-01-01T00:00:00')
				3100	return {
				3101	"tweetid": $t.tweetid,
				3102	"counthashed-gram-tokens": $tokens
				3103	}
				3104
				3105
				3106	* The expected result is:
				3107
				3108	{
				3109	"tweetid": "9",
				3110	"counthashed-gram-tokens": [ 40557178, -2002241593, 161665899, -856104603, -500544946, 693410611, 395674299, -1015235909, 1115608337, 1187999872, -31006095, -219180466, -1676061637,
				3111	1040194153, -1339307841, -1527110163, -1884722688, -179148713, -431014627, -1789789823, -1209719926, 684519765, -486734513, 1734740619, -1971673751, -932421915, -2064668066, -937135958,
				3112	-790946468, -69070309, 1561601454, 26169001, -160734571, 1330043462, -486734512, -18796768, -470303314, 113421364, 1615760212, 1688217556, 1223719184, 536568131, 1682609873, 2935161,
				3113	-414769471, -1027490137, 1602276102, 1050490461 ]
				3114	} --></div></div>
				3115	<div class="section">
				3116	<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>
				3117	<div class="section">
				3118	<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>
				3119
				3120	<ul>
				3121
				3122	<li>
				3123	<p>Syntax:</p>
				3124
				3125	<div class="source">
				3126	<div class="source">
				3127	<pre>get-year/get-month/get-day/get-hour/get-minute/get-second/get-millisecond(temporal_expression)
				3128	</pre></div></div></li>
				3129
				3130	<li>
				3131	<p>Accessors for accessing fields in a temporal value</p></li>
				3132
				3133	<li>Arguments:
				3134
				3135	<ul>
				3136
				3137	<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>
				3138	</ul></li>
				3139
				3140	<li>Return Value:
				3141
				3142	<ul>
				3143
				3144	<li>An <tt>int64</tt> value representing the field to be extracted.</li>
				3145	</ul></li>
				3146
				3147	<li>
				3148	<p>Example:</p>
				3149
				3150	<div class="source">
				3151	<div class="source">
				3152	<pre>let $c1 := date("2010-10-30")
				3153	let $c2 := datetime("1987-11-19T23:49:23.938")
				3154	let $c3 := time("12:23:34.930+07:00")
				3155	let $c4 := duration("P3Y73M632DT49H743M3948.94S")
				3156
				3157	return {"year": get-year($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)}
				3158	</pre></div></div></li>
				3159	</ul>
				3160
				3161	<ul>
				3162
				3163	<li>
				3164	<p>The expected result is:</p>
				3165
				3166	<div class="source">
				3167	<div class="source">
				3168	<pre>{ "year": 2010, "month": 11, "day": 30, "hour": 5, "min": 28, "second": 23, "ms": 94 }
				3169	</pre></div></div></li>
				3170	</ul></div>
				3171	<div class="section">
				3172	<h3><a name="adjust-datetime-for-timezone"></a>adjust-datetime-for-timezone</h3>
				3173
				3174	<ul>
				3175
				3176	<li>
				3177	<p>Syntax:</p>
				3178
				3179	<div class="source">
				3180	<div class="source">
				3181	<pre>adjust-datetime-for-timezone(datetime_expression, string_expression)
				3182	</pre></div></div></li>
				3183
				3184	<li>
				3185	<p>Adjusts the given datetime <tt>datetime_expression</tt> by applying the timezone information <tt>string_expression</tt>.</p></li>
				3186
				3187	<li>Arguments:
				3188
				3189	<ul>
				3190
				3191	<li><tt>datetime_expression</tt> : A <tt>datetime</tt> value to be adjusted.</li>
				3192
				3193	<li><tt>string_expression</tt> : A <tt>string</tt> representing the timezone information.</li>
				3194	</ul></li>
				3195
				3196	<li>Return Value:
				3197
				3198	<ul>
				3199
				3200	<li>A <tt>string</tt> value representing the new datetime after being adjusted by the timezone information.</li>
				3201	</ul></li>
				3202
				3203	<li>
				3204	<p>Example:</p>
				3205
				3206	<div class="source">
				3207	<div class="source">
				3208	<pre>use dataverse TinySocial;
				3209
				3210	for $i in dataset('TweetMessages')
				3211	return {"adjusted-send-time": adjust-datetime-for-timezone($i.send-time, "+08:00"), "message": $i.message-text}
				3212	</pre></div></div></li>
				3213	</ul>
				3214
				3215	<ul>
				3216
				3217	<li>
				3218	<p>The expected result is:</p>
				3219
				3220	<div class="source">
				3221	<div class="source">
				3222	<pre>{ "adjusted-send-time": "2008-04-26T18:10:00.000+08:00", "message": " love t-mobile its customization is good:)" }
				3223	{ "adjusted-send-time": "2010-05-13T18:10:00.000+08:00", "message": " like verizon its shortcut-menu is awesome:)" }
				3224	{ "adjusted-send-time": "2006-11-04T18:10:00.000+08:00", "message": " like motorola the speed is good:)" }
				3225	{ "adjusted-send-time": "2011-12-26T18:10:00.000+08:00", "message": " like sprint the voice-command is mind-blowing:)" }
				3226	{ "adjusted-send-time": "2006-08-04T18:10:00.000+08:00", "message": " can't stand motorola its speed is terrible:(" }
				3227	{ "adjusted-send-time": "2010-05-07T18:10:00.000+08:00", "message": " like iphone the voice-clarity is good:)" }
				3228	{ "adjusted-send-time": "2011-08-25T18:10:00.000+08:00", "message": " like samsung the platform is good" }
				3229	{ "adjusted-send-time": "2005-10-14T18:10:00.000+08:00", "message": " like t-mobile the shortcut-menu is awesome:)" }
				3230	{ "adjusted-send-time": "2012-07-21T18:10:00.000+08:00", "message": " love verizon its voicemail-service is awesome" }
				3231	{ "adjusted-send-time": "2008-01-26T18:10:00.000+08:00", "message": " hate verizon its voice-clarity is OMG:(" }
				3232	{ "adjusted-send-time": "2008-03-09T18:10:00.000+08:00", "message": " can't stand iphone its platform is terrible" }
				3233	{ "adjusted-send-time": "2010-02-13T18:10:00.000+08:00", "message": " like samsung the voice-command is amazing:)" }
				3234	</pre></div></div></li>
				3235	</ul></div>
				3236	<div class="section">
				3237	<h3><a name="adjust-time-for-timezone"></a>adjust-time-for-timezone</h3>
				3238
				3239	<ul>
				3240
				3241	<li>
				3242	<p>Syntax:</p>
				3243
				3244	<div class="source">
				3245	<div class="source">
				3246	<pre>adjust-time-for-timezone(time_expression, string_expression)
				3247	</pre></div></div></li>
				3248
				3249	<li>
				3250	<p>Adjusts the given time <tt>time_expression</tt> by applying the timezone information <tt>string_expression</tt>.</p></li>
				3251
				3252	<li>Arguments:
				3253
				3254	<ul>
				3255
				3256	<li><tt>time_expression</tt> : A <tt>time</tt> value to be adjusted.</li>
				3257
				3258	<li><tt>string_expression</tt> : A <tt>string</tt> representing the timezone information.</li>
				3259	</ul></li>
				3260
				3261	<li>Return Value:
				3262
				3263	<ul>
				3264
				3265	<li>A <tt>string</tt> value representing the new time after being adjusted by the timezone information.</li>
				3266	</ul></li>
				3267
				3268	<li>
				3269	<p>Example:</p>
				3270
				3271	<div class="source">
				3272	<div class="source">
				3273	<pre>use dataverse TinySocial;
				3274
				3275	for $i in dataset('TweetMessages')
				3276	return {"adjusted-send-time": adjust-time-for-timezone(time-from-datetime($i.send-time), "+08:00"), "message": $i.message-text}
				3277	</pre></div></div></li>
				3278	</ul>
				3279
				3280	<ul>
				3281
				3282	<li>
				3283	<p>The expected result is:</p>
				3284
				3285	<div class="source">
				3286	<div class="source">
				3287	<pre>{ "adjusted-send-time": "18:10:00.000+08:00", "message": " love t-mobile its customization is good:)" }
				3288	{ "adjusted-send-time": "18:10:00.000+08:00", "message": " like verizon its shortcut-menu is awesome:)" }
				3289	{ "adjusted-send-time": "18:10:00.000+08:00", "message": " like motorola the speed is good:)" }
				3290	{ "adjusted-send-time": "18:10:00.000+08:00", "message": " like sprint the voice-command is mind-blowing:)" }
				3291	{ "adjusted-send-time": "18:10:00.000+08:00", "message": " can't stand motorola its speed is terrible:(" }
				3292	{ "adjusted-send-time": "18:10:00.000+08:00", "message": " like iphone the voice-clarity is good:)" }
				3293	{ "adjusted-send-time": "18:10:00.000+08:00", "message": " like samsung the platform is good" }
				3294	{ "adjusted-send-time": "18:10:00.000+08:00", "message": " like t-mobile the shortcut-menu is awesome:)" }
				3295	{ "adjusted-send-time": "18:10:00.000+08:00", "message": " love verizon its voicemail-service is awesome" }
				3296	{ "adjusted-send-time": "18:10:00.000+08:00", "message": " hate verizon its voice-clarity is OMG:(" }
				3297	{ "adjusted-send-time": "18:10:00.000+08:00", "message": " can't stand iphone its platform is terrible" }
				3298	{ "adjusted-send-time": "18:10:00.000+08:00", "message": " like samsung the voice-command is amazing:)" }
				3299	</pre></div></div></li>
				3300	</ul></div>
				3301	<div class="section">
				3302	<h3><a name="calendar-duration-from-datetime"></a>calendar-duration-from-datetime</h3>
				3303
				3304	<ul>
				3305
				3306	<li>
				3307	<p>Syntax:</p>
				3308
				3309	<div class="source">
				3310	<div class="source">
				3311	<pre>calendar-duration-from-datetime(datetime_expression, duration_expression)
				3312	</pre></div></div></li>
				3313
				3314	<li>
				3315	<p>Gets a user-friendly representation of the duration <tt>duration_expression</tt> based on the given datetime <tt>datetime_expression</tt>.</p></li>
				3316
				3317	<li>Arguments:
				3318
				3319	<ul>
				3320
				3321	<li><tt>datetime_expression</tt> : A <tt>datetime</tt> value to be used as the reference time point.</li>
				3322
				3323	<li><tt>duration_expression</tt> : A <tt>duration</tt> value to be converted.</li>
				3324	</ul></li>
				3325
				3326	<li>Return Value:
				3327
				3328	<ul>
				3329
				3330	<li>A <tt>duration</tt> value with the duration as <tt>duration_expression</tt> but with a user-friendly representation.</li>
				3331	</ul></li>
				3332
				3333	<li>
				3334	<p>Example:</p>
				3335
				3336	<div class="source">
				3337	<div class="source">
				3338	<pre>use dataverse TinySocial;
				3339
				3340	for $i in dataset('TweetMessages')
				3341	where $i.send-time > datetime("2011-01-01T00:00:00")
				3342	return {"since-2011": subtract-datetime($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")))}
				3343	</pre></div></div></li>
				3344	</ul>
				3345
				3346	<ul>
				3347
				3348	<li>
				3349	<p>The expected result is:</p>
				3350
				3351	<div class="source">
				3352	<div class="source">
				3353	<pre>{ "since-2011": duration("P359DT10H10M"), "since-2011-user-friendly": duration("P11M23DT10H10M") }
				3354	{ "since-2011": duration("P236DT10H10M"), "since-2011-user-friendly": duration("P7M23DT10H10M") }
				3355	{ "since-2011": duration("P567DT10H10M"), "since-2011-user-friendly": duration("P1Y6M18DT10H10M") }
				3356	</pre></div></div></li>
				3357	</ul></div>
				3358	<div class="section">
				3359	<h3><a name="get-year-month-durationget-day-time-duration"></a>get-year-month-duration/get-day-time-duration</h3>
				3360
				3361	<ul>
				3362
				3363	<li>
				3364	<p>Syntax:</p>
				3365
				3366	<div class="source">
				3367	<div class="source">
				3368	<pre>get-year-month-duration/get-day-time-duration(duration_expression)
				3369	</pre></div></div></li>
				3370
				3371	<li>
				3372	<p>Extracts the correct <tt>duration</tt> subtype from <tt>duration_expression</tt>.</p></li>
				3373
				3374	<li>Arguments:
				3375
				3376	<ul>
				3377
				3378	<li><tt>duration_expression</tt> : A <tt>duration</tt> value to be converted.</li>
				3379	</ul></li>
				3380
				3381	<li>Return Value:
				3382
				3383	<ul>
				3384
				3385	<li>A <tt>year-month-duration</tt> value or a <tt>day-time-duration</tt> value.</li>
				3386	</ul></li>
				3387
				3388	<li>
				3389	<p>Example:</p>
				3390
				3391	<div class="source">
				3392	<div class="source">
				3393	<pre>let $i := get-year-month-duration(duration("P12M50DT10H"))
				3394	return $i;
				3395	</pre></div></div></li>
				3396	</ul>
				3397
				3398	<ul>
				3399
				3400	<li>
				3401	<p>The expected result is:</p>
				3402
				3403	<div class="source">
				3404	<div class="source">
				3405	<pre>year-month-duration("P1Y")
				3406	</pre></div></div></li>
				3407	</ul></div>
				3408	<div class="section">
				3409	<h3><a name="months-from-year-month-durationmilliseconds-from-day-time-duration"></a>months-from-year-month-duration/milliseconds-from-day-time-duration</h3>
				3410
				3411	<ul>
				3412
				3413	<li>
				3414	<p>Syntax:</p>
				3415
				3416	<div class="source">
				3417	<div class="source">
				3418	<pre>months-from-year-month-duration/milliseconds-from-day-time-duration(duration_expression)
				3419	</pre></div></div></li>
				3420
				3421	<li>
				3422	<p>Extracts the number of months or the number of milliseconds from the <tt>duration</tt> subtype.</p></li>
				3423
				3424	<li>Arguments:
				3425
				3426	<ul>
				3427
				3428	<li><tt>duration_expression</tt> : A <tt>duration</tt> of the correct subtype.</li>
				3429	</ul></li>
				3430
				3431	<li>Return Value:
				3432
				3433	<ul>
				3434
				3435	<li>An <tt>int64</tt> representing the number or months/milliseconds.</li>
				3436	</ul></li>
				3437
				3438	<li>
				3439	<p>Example:</p>
				3440
				3441	<div class="source">
				3442	<div class="source">
				3443	<pre>let $i := months-from-year-month-duration(get-year-month-duration(duration("P5Y7MT50M")))
				3444	return $i;
				3445	</pre></div></div></li>
				3446	</ul>
				3447
				3448	<ul>
				3449
				3450	<li>
				3451	<p>The expected result is:</p>
				3452
				3453	<div class="source">
				3454	<div class="source">
				3455	<pre>67
				3456	</pre></div></div></li>
				3457	</ul></div>
				3458	<div class="section">
				3459	<h3><a name="duration-from-monthsduration-from-ms"></a>duration-from-months/duration-from-ms</h3>
				3460
				3461	<ul>
				3462
				3463	<li>
				3464	<p>Syntax:</p>
				3465
				3466	<div class="source">
				3467	<div class="source">
				3468	<pre>duration-from-months/duration-from-ms(number_expression)
				3469	</pre></div></div></li>
				3470
				3471	<li>
				3472	<p>Creates a <tt>duration</tt> from <tt>number_expression</tt>.</p></li>
				3473
				3474	<li>Arguments:
				3475
				3476	<ul>
				3477
				3478	<li><tt>number_expression</tt> : An <tt>int64</tt> representing the number of months/milliseconds</li>
				3479	</ul></li>
				3480
				3481	<li>Return Value:
				3482
				3483	<ul>
				3484
				3485	<li>A <tt>duration</tt> containing <tt>number_expression</tt> value for months/milliseconds</li>
				3486	</ul></li>
				3487
				3488	<li>
				3489	<p>Example:</p>
				3490
				3491	<div class="source">
				3492	<div class="source">
				3493	<pre>let $i := duration-from-months(8)
				3494	return $i;
				3495	</pre></div></div></li>
				3496
				3497	<li>
				3498	<p>The expected result is:</p>
				3499
				3500	<div class="source">
				3501	<div class="source">
				3502	<pre>duration("P8M")
				3503	</pre></div></div></li>
				3504	</ul></div>
				3505	<div class="section">
				3506	<h3><a name="duration-from-interval"></a>duration-from-interval</h3>
				3507
				3508	<ul>
				3509
				3510	<li>
				3511	<p>Syntax:</p>
				3512
				3513	<div class="source">
				3514	<div class="source">
				3515	<pre>duration-from-interval(interval_expression)
				3516	</pre></div></div></li>
				3517
				3518	<li>
				3519	<p>Creates a <tt>duration</tt> from <tt>interval_expression</tt>.</p></li>
				3520
				3521	<li>Arguments:
				3522
				3523	<ul>
				3524
				3525	<li><tt>interval_expression</tt> : An <tt>interval</tt> value</li>
				3526	</ul></li>
				3527
				3528	<li>Return Value:
				3529
				3530	<ul>
				3531
				3532	<li>A <tt>duration</tt> repesenting the time in the <tt>interval_expression</tt></li>
				3533	</ul></li>
				3534
				3535	<li>
				3536	<p>Example:</p>
				3537
				3538	<div class="source">
				3539	<div class="source">
				3540	<pre>let $itv1 := interval-from-date("2010-10-30", "2010-12-21")
				3541	let $itv2 := interval-from-datetime("2012-06-26T01:01:01.111", "2012-07-27T02:02:02.222")
				3542	let $itv3 := interval-from-time("12:32:38", "20:29:20")
				3543
				3544	return { "dr1" : duration-from-interval($itv1),
				3545	"dr2" : duration-from-interval($itv2),
				3546	"dr3" : duration-from-interval($itv3),
				3547	"dr4" : duration-from-interval(null) }
				3548	</pre></div></div></li>
				3549
				3550	<li>
				3551	<p>The expected result is:</p>
				3552
				3553	<div class="source">
				3554	<div class="source">
				3555	<pre>{ "dr1": day-time-duration("P52D"),
				3556	"dr2": day-time-duration("P31DT1H1M1.111S"),
				3557	"dr3": day-time-duration("PT7H56M42S"),
				3558	"dr4": null }
				3559	</pre></div></div></li>
				3560	</ul></div>
				3561	<div class="section">
				3562	<h3><a name="current-date"></a>current-date</h3>
				3563
				3564	<ul>
				3565
				3566	<li>
				3567	<p>Syntax:</p>
				3568
				3569	<div class="source">
				3570	<div class="source">
				3571	<pre>current-date()
				3572	</pre></div></div></li>
				3573
				3574	<li>
				3575	<p>Gets the current date.</p></li>
				3576
				3577	<li>Arguments: None</li>
				3578
				3579	<li>Return Value:
				3580
				3581	<ul>
				3582
				3583	<li>A <tt>date</tt> value of the date when the function is called.</li>
				3584	</ul></li>
				3585	</ul></div>
				3586	<div class="section">
				3587	<h3><a name="current-time"></a>current-time</h3>
				3588
				3589	<ul>
				3590
				3591	<li>
				3592	<p>Syntax:</p>
				3593
				3594	<div class="source">
				3595	<div class="source">
				3596	<pre>current-time()
				3597	</pre></div></div></li>
				3598
				3599	<li>
				3600	<p>Get the current time</p></li>
				3601
				3602	<li>Arguments: None</li>
				3603
				3604	<li>Return Value:
				3605
				3606	<ul>
				3607
				3608	<li>A <tt>time</tt> value of the time when the function is called.</li>
				3609	</ul></li>
				3610	</ul></div>
				3611	<div class="section">
				3612	<h3><a name="current-datetime"></a>current-datetime</h3>
				3613
				3614	<ul>
				3615
				3616	<li>
				3617	<p>Syntax:</p>
				3618
				3619	<div class="source">
				3620	<div class="source">
				3621	<pre>current-datetime()
				3622	</pre></div></div></li>
				3623
				3624	<li>
				3625	<p>Get the current datetime</p></li>
				3626
				3627	<li>Arguments: None</li>
				3628
				3629	<li>Return Value:
				3630
				3631	<ul>
				3632
				3633	<li>A <tt>datetime</tt> value of the datetime when the function is called.</li>
				3634	</ul></li>
				3635
				3636	<li>
				3637	<p>Example:</p>
				3638
				3639	<div class="source">
				3640	<div class="source">
				3641	<pre>{"current-date": current-date(),
				3642	"current-time": current-time(),
				3643	"current-datetime": current-datetime()}
				3644	</pre></div></div></li>
				3645	</ul>
				3646
				3647	<ul>
				3648
				3649	<li>
				3650	<p>The expected result is:</p>
				3651
				3652	<div class="source">
				3653	<div class="source">
				3654	<pre>{ "current-date": date("2013-04-06"),
				3655	"current-time": time("00:48:44.093Z"),
				3656	"current-datetime": datetime("2013-04-06T00:48:44.093Z") }
				3657	</pre></div></div></li>
				3658	</ul></div>
				3659	<div class="section">
				3660	<h3><a name="get-date-from-datetime"></a>get-date-from-datetime</h3>
				3661
				3662	<ul>
				3663
				3664	<li>
				3665	<p>Syntax:</p>
				3666
				3667	<div class="source">
				3668	<div class="source">
				3669	<pre>get-date-from-datetime(datetime_expression)
				3670	</pre></div></div></li>
				3671
				3672	<li>
				3673	<p>Gets the date value from the given datetime value <tt>datetime_expression</tt>.</p></li>
				3674
				3675	<li>Arguments:
				3676
				3677	<ul>
				3678
				3679	<li><tt>datetime_expression</tt>: A <tt>datetime</tt> value to be extracted from.</li>
				3680	</ul></li>
				3681
				3682	<li>Return Value:
				3683
				3684	<ul>
				3685
				3686	<li>A <tt>date</tt> value from the datetime.</li>
				3687	</ul></li>
				3688	</ul></div>
				3689	<div class="section">
				3690	<h3><a name="get-time-from-datetime"></a>get-time-from-datetime</h3>
				3691
				3692	<ul>
				3693
				3694	<li>
				3695	<p>Syntax:</p>
				3696
				3697	<div class="source">
				3698	<div class="source">
				3699	<pre>get-time-from-datetime(datetime_expression)
				3700	</pre></div></div></li>
				3701
				3702	<li>
				3703	<p>Get the time value from the given datetime value <tt>datetime_expression</tt></p></li>
				3704
				3705	<li>Arguments:
				3706
				3707	<ul>
				3708
				3709	<li><tt>datetime_expression</tt>: A <tt>datetime</tt> value to be extracted from</li>
				3710	</ul></li>
				3711
				3712	<li>Return Value:
				3713
				3714	<ul>
				3715
				3716	<li>A <tt>time</tt> value from the datetime.</li>
				3717	</ul></li>
				3718
				3719	<li>
				3720	<p>Example:</p>
				3721
				3722	<div class="source">
				3723	<div class="source">
				3724	<pre>use dataverse TinySocial;
				3725
				3726	for $i in dataset('TweetMessages')
				3727	where $i.send-time > datetime("2011-01-01T00:00:00")
				3728	return {"send-date": get-date-from-datetime($i.send-time), "send-time": get-time-from-datetime($i.send-time)}
				3729	</pre></div></div></li>
				3730	</ul>
				3731
				3732	<ul>
				3733
				3734	<li>
				3735	<p>The expected result is:</p>
				3736
				3737	<div class="source">
				3738	<div class="source">
				3739	<pre>{ "send-date": date("2011-12-26"), "send-time": time("10:10:00.000Z") }
				3740	{ "send-date": date("2011-08-25"), "send-time": time("10:10:00.000Z") }
				3741	{ "send-date": date("2012-07-21"), "send-time": time("10:10:00.000Z") }
				3742	</pre></div></div></li>
				3743	</ul></div>
				3744	<div class="section">
				3745	<h3><a name="day-of-week"></a>day-of-week</h3>
				3746
				3747	<ul>
				3748
				3749	<li>
				3750	<p>Syntax:</p>
				3751
				3752	<div class="source">
				3753	<div class="source">
				3754	<pre>day-of-week(date_expression)
				3755	</pre></div></div></li>
				3756
				3757	<li>
				3758	<p>Finds the day of the week for a given date (1-7)</p></li>
				3759
				3760	<li>Arguments:
				3761
				3762	<ul>
				3763
				3764	<li><tt>date_expression</tt>: A <tt>date</tt> value (Can also be a <tt>datetime</tt>)</li>
				3765	</ul></li>
				3766
				3767	<li>Return Value:
				3768
				3769	<ul>
				3770
				3771	<li>An <tt>int8</tt> representing the day of the week (1-7)</li>
				3772	</ul></li>
				3773
				3774	<li>
				3775	<p>Example:</p>
				3776
				3777	<div class="source">
				3778	<div class="source">
				3779	<pre>let $i := day-of-week( datetime("2012-12-30T12:12:12.039Z"))
				3780	return $i;
				3781	</pre></div></div></li>
				3782	</ul>
				3783
				3784	<ul>
				3785
				3786	<li>
				3787	<p>The expected result is:</p>
				3788
				3789	<div class="source">
				3790	<div class="source">
				3791	<pre>7
				3792	</pre></div></div></li>
				3793	</ul></div>
				3794	<div class="section">
				3795	<h3><a name="date-from-unix-time-in-days"></a>date-from-unix-time-in-days</h3>
				3796
				3797	<ul>
				3798
				3799	<li>
				3800	<p>Syntax:</p>
				3801
				3802	<div class="source">
				3803	<div class="source">
				3804	<pre>date-from-unix-time-in-days(numeric_expression)
				3805	</pre></div></div></li>
				3806
				3807	<li>
				3808	<p>Gets a date representing the time after <tt>numeric_expression</tt> days since 1970-01-01.</p></li>
				3809
				3810	<li>Arguments:
				3811
				3812	<ul>
				3813
				3814	<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>
				3815	</ul></li>
				3816
				3817	<li>Return Value:
				3818
				3819	<ul>
				3820
				3821	<li>A <tt>date</tt> value as the time after <tt>numeric_expression</tt> days since 1970-01-01.</li>
				3822	</ul></li>
				3823	</ul></div>
				3824	<div class="section">
				3825	<h3><a name="datetime-from-unix-time-in-ms"></a>datetime-from-unix-time-in-ms</h3>
				3826
				3827	<ul>
				3828
				3829	<li>
				3830	<p>Syntax:</p>
				3831
				3832	<div class="source">
				3833	<div class="source">
				3834	<pre>datetime-from-unix-time-in-ms(numeric_expression)
				3835	</pre></div></div></li>
				3836
				3837	<li>
				3838	<p>Gets a datetime representing the time after <tt>numeric_expression</tt> milliseconds since 1970-01-01T00:00:00Z.</p></li>
				3839
				3840	<li>Arguments:
				3841
				3842	<ul>
				3843
				3844	<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>
				3845	</ul></li>
				3846
				3847	<li>Return Value:
				3848
				3849	<ul>
				3850
				3851	<li>A <tt>datetime</tt> value as the time after <tt>numeric_expression</tt> milliseconds since 1970-01-01T00:00:00Z.</li>
				3852	</ul></li>
				3853	</ul></div>
				3854	<div class="section">
				3855	<h3><a name="datetime-from-unix-time-in-secs"></a>datetime-from-unix-time-in-secs</h3>
				3856
				3857	<ul>
				3858
				3859	<li>
				3860	<p>Syntax:</p>
				3861
				3862	<div class="source">
				3863	<div class="source">
				3864	<pre>datetime-from-unix-time-in-secs(numeric_expression)
				3865	</pre></div></div></li>
				3866
				3867	<li>
				3868	<p>Gets a datetime representing the time after <tt>numeric_expression</tt> seconds since 1970-01-01T00:00:00Z.</p></li>
				3869
				3870	<li>Arguments:
				3871
				3872	<ul>
				3873
				3874	<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>
				3875	</ul></li>
				3876
				3877	<li>Return Value:
				3878
				3879	<ul>
				3880
				3881	<li>A <tt>datetime</tt> value as the time after <tt>numeric_expression</tt> seconds since 1970-01-01T00:00:00Z.</li>
				3882	</ul></li>
				3883	</ul></div>
				3884	<div class="section">
				3885	<h3><a name="datetime-from-date-time"></a>datetime-from-date-time</h3>
				3886
				3887	<ul>
				3888
				3889	<li>Syntax:</li>
				3890	</ul>
				3891	<p>datetime-from-date-time(date_expression,time_expression)</p>
				3892
				3893	<ul>
				3894
				3895	<li>Gets a datetime representing the combination of <tt>date_expression</tt> and <tt>time_expression</tt>
				3896
				3897	<ul>
				3898
				3899	<li>Arguments:</li>
				3900
				3901	<li><tt>date_expression</tt>: A <tt>date</tt> value</li>
				3902
				3903	<li><tt>time_expression</tt> A <tt>time</tt> value</li>
				3904	</ul></li>
				3905
				3906	<li>Return Value:
				3907
				3908	<ul>
				3909
				3910	<li>A <tt>datetime</tt> value by combining <tt>date_expression</tt> and <tt>time_expression</tt></li>
				3911	</ul></li>
				3912	</ul></div>
				3913	<div class="section">
				3914	<h3><a name="time-from-unix-time-in-ms"></a>time-from-unix-time-in-ms</h3>
				3915
				3916	<ul>
				3917
				3918	<li>
				3919	<p>Syntax:</p>
				3920
				3921	<div class="source">
				3922	<div class="source">
				3923	<pre>time-from-unix-time-in-ms(numeric_expression)
				3924	</pre></div></div></li>
				3925
				3926	<li>
				3927	<p>Gets a time representing the time after <tt>numeric_expression</tt> milliseconds since 00:00:00.000Z.</p></li>
				3928
				3929	<li>Arguments:
				3930
				3931	<ul>
				3932
				3933	<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>
				3934	</ul></li>
				3935
				3936	<li>Return Value:
				3937
				3938	<ul>
				3939
				3940	<li>A <tt>time</tt> value as the time after <tt>numeric_expression</tt> milliseconds since 00:00:00.000Z.</li>
				3941	</ul></li>
				3942
				3943	<li>
				3944	<p>Example:</p>
				3945
				3946	<div class="source">
				3947	<div class="source">
				3948	<pre>use dataverse TinySocial;
				3949
				3950	let $d := date-from-unix-time-in-days(15800)
				3951	let $dt := datetime-from-unix-time-in-ms(1365139700000)
				3952	let $t := time-from-unix-time-in-ms(3748)
				3953	return {"date": $d, "datetime": $dt, "time": $t}
				3954	</pre></div></div></li>
				3955	</ul>
				3956
				3957	<ul>
				3958
				3959	<li>
				3960	<p>The expected result is:</p>
				3961
				3962	<div class="source">
				3963	<div class="source">
				3964	<pre>{ "date": date("2013-04-05"), "datetime": datetime("2013-04-05T05:28:20.000Z"), "time": time("00:00:03.748Z") }
				3965	</pre></div></div></li>
				3966	</ul></div>
				3967	<div class="section">
				3968	<h3><a name="parse-dateparse-timeparse-datetime"></a>parse-date/parse-time/parse-datetime</h3>
				3969
				3970	<ul>
				3971
				3972	<li>Syntax:</li>
				3973	</ul>
				3974	<p>parse-date/parse-time/parse-datetime(date_expression,formatting_expression)</p>
				3975
				3976	<ul>
				3977
				3978	<li>Creates a <tt>date/time/date-time</tt> value by treating <tt>date_expression</tt> with formatting <tt>formatting_expression</tt></li>
				3979
				3980	<li>Arguments:
				3981
				3982	<ul>
				3983
				3984	<li><tt>date_expression</tt>: A <tt>string</tt> value representing the <tt>date/time/datetime</tt>.</li>
				3985
				3986	<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>
				3987
				3988	<li><tt>h</tt> hours</li>
				3989
				3990	<li><tt>m</tt> minutes</li>
				3991
				3992	<li><tt>s</tt> seconds</li>
				3993
				3994	<li><tt>n</tt> milliseconds</li>
				3995
				3996	<li><tt>a</tt> am/pm</li>
				3997
				3998	<li><tt>z</tt> timezone</li>
				3999
				4000	<li><tt>Y</tt> year</li>
				4001
				4002	<li><tt>M</tt> month</li>
				4003
				4004	<li><tt>D</tt> day</li>
				4005
				4006	<li><tt>W</tt> weekday</li>
				4007
				4008	<li><tt>-</tt>, <tt>'</tt>, <tt>/</tt>, <tt>.</tt>, <tt>,</tt>, <tt>T</tt> seperators for both time and date</li>
				4009	</ul></li>
				4010
				4011	<li>Return Value:
				4012
				4013	<ul>
				4014
				4015	<li>A <tt>date/time/date-time</tt> value corresponding to <tt>date_expression</tt></li>
				4016	</ul></li>
				4017
				4018	<li>
				4019	<p>Example:</p>
				4020
				4021	<div class="source">
				4022	<div class="source">
				4023	<pre>let $i := parse-time("30:30","m:s")
				4024	return $i;
				4025	</pre></div></div></li>
				4026
				4027	<li>
				4028	<p>The expected result is:</p>
				4029
				4030	<div class="source">
				4031	<div class="source">
				4032	<pre>time("00:30:30.000Z")
				4033	</pre></div></div></li>
				4034	</ul></div>
				4035	<div class="section">
				4036	<h3><a name="print-dateprint-timeprint-datetime"></a>print-date/print-time/print-datetime</h3>
				4037
				4038	<ul>
				4039
				4040	<li>Syntax:</li>
				4041	</ul>
				4042	<p>print-date/print-time/print-datetime(date_expression,formatting_expression)</p>
				4043
				4044	<ul>
				4045
				4046	<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>
				4047
				4048	<li>Arguments:
				4049
				4050	<ul>
				4051
				4052	<li><tt>date_expression</tt>: A <tt>date/time/datetime</tt> value.</li>
				4053
				4054	<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>
				4055
				4056	<li><tt>h</tt> hours</li>
				4057
				4058	<li><tt>m</tt> minutes</li>
				4059
				4060	<li><tt>s</tt> seconds</li>
				4061
				4062	<li><tt>n</tt> milliseconds</li>
				4063
				4064	<li><tt>a</tt> am/pm</li>
				4065
				4066	<li><tt>z</tt> timezone</li>
				4067
				4068	<li><tt>Y</tt> year</li>
				4069
				4070	<li><tt>M</tt> month</li>
				4071
				4072	<li><tt>D</tt> day</li>
				4073
				4074	<li><tt>W</tt> weekday</li>
				4075
				4076	<li><tt>-</tt>, <tt>'</tt>, <tt>/</tt>, <tt>.</tt>, <tt>,</tt>, <tt>T</tt> seperators for both time and date</li>
				4077	</ul></li>
				4078
				4079	<li>Return Value:
				4080
				4081	<ul>
				4082
				4083	<li>A <tt>string</tt> value corresponding to <tt>date_expression</tt></li>
				4084	</ul></li>
				4085
				4086	<li>
				4087	<p>Example:</p>
				4088
				4089	<div class="source">
				4090	<div class="source">
				4091	<pre>let $i := print-time(time("00:30:30.000Z"),"m:s")
				4092	return $i;
				4093	</pre></div></div></li>
				4094
				4095	<li>
				4096	<p>The expected result is:</p>
				4097
				4098	<div class="source">
				4099	<div class="source">
				4100	<pre>"30:30"
				4101	</pre></div></div></li>
				4102	</ul></div>
				4103	<div class="section">
				4104	<h3><a name="get-interval-start_get-interval-end"></a>get-interval-start, get-interval-end</h3>
				4105
				4106	<ul>
				4107
				4108	<li>
				4109	<p>Syntax:</p>
				4110
				4111	<div class="source">
				4112	<div class="source">
				4113	<pre>get-interval-start/get-interval-end(interval)
				4114	</pre></div></div></li>
				4115
				4116	<li>
				4117	<p>Gets the start/end of the given interval.</p></li>
				4118
				4119	<li>Arguments:
				4120
				4121	<ul>
				4122
				4123	<li><tt>interval</tt>: the interval to be accessed.</li>
				4124	</ul></li>
				4125
				4126	<li>Return Value:
				4127
				4128	<ul>
				4129
				4130	<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>
				4131	</ul></li>
				4132
				4133	<li>
				4134	<p>Example:</p>
				4135
				4136	<div class="source">
				4137	<div class="source">
				4138	<pre>let $itv := interval-start-from-date("1984-01-01", "P1Y")
				4139	return {"start": get-interval-start($itv), "end": get-interval-end($itv)}
				4140	</pre></div></div></li>
				4141	</ul>
				4142
				4143	<ul>
				4144
				4145	<li>
				4146	<p>The expected result is:</p>
				4147
				4148	<div class="source">
				4149	<div class="source">
				4150	<pre>{ "start": date("1984-01-01"), "end": date("1985-01-01") }
				4151	</pre></div></div></li>
				4152	</ul></div>
				4153	<div class="section">
				4154	<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>
				4155
				4156	<ul>
				4157
				4158	<li>
				4159	<p>Syntax:</p>
				4160
				4161	<div class="source">
				4162	<div class="source">
				4163	<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)
				4164	</pre></div></div></li>
				4165
				4166	<li>
				4167	<p>Gets the start/end of the given interval for the specific date/datetime/time type.</p></li>
				4168
				4169	<li>Arguments:
				4170
				4171	<ul>
				4172
				4173	<li><tt>interval</tt>: the interval to be accessed.</li>
				4174	</ul></li>
				4175
				4176	<li>Return Value:
				4177
				4178	<ul>
				4179
				4180	<li>A <tt>time</tt>, <tt>date</tt>, or <tt>datetime</tt> (depending on the function) representing the starting or ending time.</li>
				4181	</ul></li>
				4182
				4183	<li>
				4184	<p>Example:</p>
				4185
				4186	<div class="source">
				4187	<div class="source">
				4188	<pre>let $itv1 := interval-start-from-date("1984-01-01", "P1Y")
				4189	let $itv2 := interval-start-from-datetime("1984-01-01T08:30:00.000", "P1Y1H")
				4190	let $itv3 := interval-start-from-time("08:30:00.000", "P1H")
				4191	return {"start": get-interval-start-date($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)}
				4192	</pre></div></div></li>
				4193	</ul>
				4194
				4195	<ul>
				4196
				4197	<li>
				4198	<p>The expected result is:</p>
				4199
				4200	<div class="source">
				4201	<div class="source">
				4202	<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") }
				4203	</pre></div></div></li>
				4204	</ul></div>
				4205	<div class="section">
				4206	<h3><a name="get-overlapping-interval"></a>get-overlapping-interval</h3>
				4207
				4208	<ul>
				4209
				4210	<li>
				4211	<p>Syntax:</p>
				4212
				4213	<div class="source">
				4214	<div class="source">
				4215	<pre>get-overlapping-interval(interval_expression_1, interval_expression_2)
				4216	</pre></div></div></li>
				4217
				4218	<li>
				4219	<p>Gets the start/end of the given interval for the specific date/datetime/time type.</p></li>
				4220
				4221	<li>Arguments:
				4222
				4223	<ul>
				4224
				4225	<li><tt>interval_expression_1</tt>: an <tt>interval</tt> value</li>
				4226
				4227	<li><tt>interval_expression_2</tt>: an <tt>interval</tt> value</li>
				4228	</ul></li>
				4229
				4230	<li>Return Value:
				4231
				4232	<ul>
				4233
				4234	<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>
				4235	</ul></li>
				4236
				4237	<li>
				4238	<p>Example:</p>
				4239
				4240	<div class="source">
				4241	<div class="source">
				4242	<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"))),
				4243	"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"))),
				4244	"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"))),
				4245	"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"))),
				4246	"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"))),
				4247	"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"))) }
				4248	</pre></div></div></li>
				4249
				4250	<li>
				4251	<p>The expected result is:</p>
				4252
				4253	<div class="source">
				4254	<div class="source">
				4255	<pre>{ "overlap1": interval-time("12:23:39.000Z, 18:27:19.000Z"),
				4256	"overlap2": null,
				4257	"overlap3": null,
				4258	"overlap4": interval-date("2013-01-01, 2014-01-01"),
				4259	"overlap5": interval-datetime("1989-03-04T12:23:39.000Z, 2000-10-30T18:27:19.000Z"),
				4260	"overlap6": null }
				4261	</pre></div></div></li>
				4262	</ul></div>
				4263	<div class="section">
				4264	<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>
				4265	<p>See the <a href="allens.html">Allen’s Relations</a>.</p></div>
				4266	<div class="section">
				4267	<h3><a name="interval-bin"></a>interval-bin</h3>
				4268
				4269	<ul>
				4270
				4271	<li>
				4272	<p>Syntax:</p>
				4273
				4274	<div class="source">
				4275	<div class="source">
				4276	<pre>interval-bin(time-to-bin, time-bin-anchor, duration-bin-size)
				4277	</pre></div></div></li>
				4278
				4279	<li>
				4280	<p>Return the <tt>interval</tt> value representing the bin containing the <tt>time-to-bin</tt> value.</p></li>
				4281
				4282	<li>Arguments:
				4283
				4284	<ul>
				4285
				4286	<li><tt>time-to-bin</tt>: a date/time/datetime value representing the time to be binned.</li>
				4287
				4288	<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>
				4289
				4290	<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:
				4291
				4292	<ul>
				4293
				4294	<li>datetime +\|- year-month-duration</li>
				4295
				4296	<li>datetime +\|- day-time-duration</li>
				4297
				4298	<li>date +\|- year-month-duration</li>
				4299
				4300	<li>date +\|- day-time-duration</li>
				4301
				4302	<li>time +\|- day-time-duration</li>
				4303	</ul></li>
				4304	</ul></li>
				4305
				4306	<li>Return Value:
				4307
				4308	<ul>
				4309
				4310	<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>
				4311	</ul></li>
				4312
				4313	<li>
				4314	<p>Example:</p>
				4315
				4316	<div class="source">
				4317	<div class="source">
				4318	<pre>let $c1 := date("2010-10-30")
				4319	let $c2 := datetime("-1987-11-19T23:49:23.938")
				4320	let $c3 := time("12:23:34.930+07:00")
				4321
				4322	return { "bin1": interval-bin($c1, date("1990-01-01"), year-month-duration("P1Y")),
				4323	"bin2": interval-bin($c2, datetime("1990-01-01T00:00:00.000Z"), year-month-duration("P6M")),
				4324	"bin3": interval-bin($c3, time("00:00:00"), day-time-duration("PD1M")),
				4325	"bin4": interval-bin($c2, datetime("2013-01-01T00:00:00.000"), day-time-duration("PT24H"))
				4326	</pre></div></div> }</li>
				4327
				4328	<li>
				4329	<p>The expected result is:</p>
				4330
				4331	<div class="source">
				4332	<div class="source">
				4333	<pre>{ "bin1": interval-date("2010-01-01, 2011-01-01"),
				4334	"bin2": interval-datetime("-1987-07-01T00:00:00.000Z, -1986-01-01T00:00:00.000Z"),
				4335	"bin3": interval-time("05:23:00.000Z, 05:24:00.000Z"),
				4336	"bin4": interval-datetime("-1987-11-19T00:00:00.000Z, -1987-11-20T00:00:00.000Z")}
				4337	</pre></div></div></li>
				4338	</ul></div>
				4339	<div class="section">
				4340	<h3><a name="interval-from-date"></a>interval-from-date</h3>
				4341
				4342	<ul>
				4343
				4344	<li>
				4345	<p>Syntax:</p>
				4346
				4347	<div class="source">
				4348	<div class="source">
				4349	<pre>interval-from-date(string_expression1, string_expression2)
				4350	</pre></div></div></li>
				4351
				4352	<li>
				4353	<p>Constructor function for the <tt>interval</tt> type by parsing two date strings.</p></li>
				4354
				4355	<li>Arguments:
				4356
				4357	<ul>
				4358
				4359	<li><tt>string_expression1</tt> : The <tt>string</tt> value representing the starting date.</li>
				4360
				4361	<li><tt>string_expression2</tt> : The <tt>string</tt> value representing the ending date.</li>
				4362	</ul></li>
				4363
				4364	<li>Return Value:
				4365
				4366	<ul>
				4367
				4368	<li>An <tt>interval</tt> value between the two dates.</li>
				4369	</ul></li>
				4370
				4371	<li>
				4372	<p>Example:</p>
				4373
				4374	<div class="source">
				4375	<div class="source">
				4376	<pre>{"date-interval": interval-from-date("2012-01-01", "2013-04-01")}
				4377	</pre></div></div></li>
				4378	</ul>
				4379
				4380	<ul>
				4381
				4382	<li>
				4383	<p>The expected result is:</p>
				4384
				4385	<div class="source">
				4386	<div class="source">
				4387	<pre>{ "date-interval": interval-date("2012-01-01, 2013-04-01") }
				4388	</pre></div></div></li>
				4389	</ul></div>
				4390	<div class="section">
				4391	<h3><a name="interval-from-time"></a>interval-from-time</h3>
				4392
				4393	<ul>
				4394
				4395	<li>
				4396	<p>Syntax:</p>
				4397
				4398	<div class="source">
				4399	<div class="source">
				4400	<pre>interval-from-time(string_expression1, string_expression2)
				4401	</pre></div></div></li>
				4402
				4403	<li>
				4404	<p>Constructor function for the <tt>interval</tt> type by parsing two time strings.</p></li>
				4405
				4406	<li>Arguments:
				4407
				4408	<ul>
				4409
				4410	<li><tt>string_expression1</tt> : The <tt>string</tt> value representing the starting time.</li>
				4411
				4412	<li><tt>string_expression2</tt> : The <tt>string</tt> value representing the ending time.</li>
				4413	</ul></li>
				4414
				4415	<li>Return Value:
				4416
				4417	<ul>
				4418
				4419	<li>An <tt>interval</tt> value between the two times.</li>
				4420	</ul></li>
				4421
				4422	<li>
				4423	<p>Example:</p>
				4424
				4425	<div class="source">
				4426	<div class="source">
				4427	<pre>{"time-interval": interval-from-time("12:23:34.456Z", "233445567+0800")}
				4428	</pre></div></div></li>
				4429	</ul>
				4430
				4431	<ul>
				4432
				4433	<li>
				4434	<p>The expected result is:</p>
				4435
				4436	<div class="source">
				4437	<div class="source">
				4438	<pre>{ "time-interval": interval-time("12:23:34.456Z, 15:34:45.567Z") }
				4439	</pre></div></div></li>
				4440	</ul></div>
				4441	<div class="section">
				4442	<h3><a name="interval-from-datetime"></a>interval-from-datetime</h3>
				4443
				4444	<ul>
				4445
				4446	<li>
				4447	<p>Syntax:</p>
				4448
				4449	<div class="source">
				4450	<div class="source">
				4451	<pre>interval-from-datetime(string_expression1, string_expression2)
				4452	</pre></div></div></li>
				4453
				4454	<li>
				4455	<p>Constructor function for <tt>interval</tt> type by parsing two datetime strings.</p></li>
				4456
				4457	<li>Arguments:
				4458
				4459	<ul>
				4460
				4461	<li><tt>string_expression1</tt> : The <tt>string</tt> value representing the starting datetime.</li>
				4462
				4463	<li><tt>string_expression2</tt> : The <tt>string</tt> value representing the ending datetime.</li>
				4464	</ul></li>
				4465
				4466	<li>Return Value:
				4467
				4468	<ul>
				4469
				4470	<li>An <tt>interval</tt> value between the two datetimes.</li>
				4471	</ul></li>
				4472
				4473	<li>
				4474	<p>Example:</p>
				4475
				4476	<div class="source">
				4477	<div class="source">
				4478	<pre>{"datetime-interval": interval-from-datetime("2012-01-01T12:23:34.456+08:00", "20130401T153445567Z")}
				4479	</pre></div></div></li>
				4480	</ul>
				4481
				4482	<ul>
				4483
				4484	<li>
				4485	<p>The expected result is:</p>
				4486
				4487	<div class="source">
				4488	<div class="source">
				4489	<pre>{ "datetime-interval": interval-datetime("2012-01-01T04:23:34.456Z, 2013-04-01T15:34:45.567Z") }
				4490	</pre></div></div></li>
				4491	</ul></div>
				4492	<div class="section">
				4493	<h3><a name="interval-start-from-datetimedatetime"></a>interval-start-from-date/time/datetime</h3>
				4494
				4495	<ul>
				4496
				4497	<li>
				4498	<p>Syntax:</p>
				4499
				4500	<div class="source">
				4501	<div class="source">
				4502	<pre>interval-start-from-date/time/datetime(date/time/datetime, duration)
				4503	</pre></div></div></li>
				4504
				4505	<li>
				4506	<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>
				4507
				4508	<li>Arguments:
				4509
				4510	<ul>
				4511
				4512	<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>
				4513
				4514	<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>
				4515	</ul></li>
				4516
				4517	<li>Return Value:
				4518
				4519	<ul>
				4520
				4521	<li>An <tt>interval</tt> value representing the interval starting from the given time point with the length of duration.</li>
				4522	</ul></li>
				4523
				4524	<li>
				4525	<p>Example:</p>
				4526
				4527	<div class="source">
				4528	<div class="source">
				4529	<pre>let $itv1 := interval-start-from-date("1984-01-01", "P1Y")
				4530	let $itv2 := interval-start-from-time(time("02:23:28.394"), "PT3H24M")
				4531	let $itv3 := interval-start-from-datetime("1999-09-09T09:09:09.999", duration("P2M30D"))
				4532	return {"interval1": $itv1, "interval2": $itv2, "interval3": $itv3}
				4533	</pre></div></div></li>
				4534
				4535	<li>
				4536	<p>The expectecd result is:</p>
				4537
				4538	<div class="source">
				4539	<div class="source">
				4540	<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") }
				4541	</pre></div></div></li>
				4542	</ul></div>
				4543	<div class="section">
				4544	<h3><a name="overlap-bins"></a>overlap-bins</h3>
				4545
				4546	<ul>
				4547
				4548	<li>
				4549	<p>Return Value:</p>
				4550
				4551	<ul>
				4552
				4553	<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>
				4554	</ul></li>
				4555
				4556	<li>
				4557	<p>Syntax:</p>
				4558
				4559	<div class="source">
				4560	<div class="source">
				4561	<pre>overlap-bins(interval_expression, time-bin-anchor, duration-bin-size)
				4562	</pre></div></div></li>
				4563
				4564	<li>
				4565	<p>Returns an ordered list of <tt>interval</tt> values representing each bin that is overlapping the <tt>interval_expression</tt>.</p></li>
				4566
				4567	<li>Arguments:
				4568
				4569	<ul>
				4570
				4571	<li><tt>interval_expression</tt>: an <tt>interval</tt> value</li>
				4572
				4573	<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>
				4574
				4575	<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:
				4576
				4577	<ul>
				4578
				4579	<li>datetime +\|- year-month-duration</li>
				4580
				4581	<li>datetime +\|- day-time-duration</li>
				4582
				4583	<li>date +\|- year-month-duration</li>
				4584
				4585	<li>date +\|- day-time-duration</li>
				4586
				4587	<li>time +\|- day-time-duration</li>
				4588	</ul></li>
				4589	</ul></li>
				4590
				4591	<li>Return Value:
				4592
				4593	<ul>
				4594
				4595	<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>
				4596	</ul></li>
				4597
				4598	<li>
				4599	<p>Example:</p>
				4600
				4601	<div class="source">
				4602	<div class="source">
				4603	<pre>let $itv1 := interval-from-time(time("17:23:37"), time("18:30:21"))
				4604	let $itv2 := interval-from-date(date("1984-03-17"), date("2013-08-22"))
				4605	let $itv3 := interval-from-datetime(datetime("1800-01-01T23:59:48.938"), datetime("2015-07-26T13:28:30.218"))
				4606	return { "timebins": overlap-bins($itv1, time("00:00:00"), day-time-duration("PT30M")),
				4607	"datebins": overlap-bins($itv2, date("1990-01-01"), year-month-duration("P20Y")),
				4608	"datetimebins": overlap-bins($itv3, datetime("1900-01-01T00:00:00.000"), year-month-duration("P100Y")) }
				4609	</pre></div></div></li>
				4610
				4611	<li>
				4612	<p>The expected result is:</p>
				4613
				4614	<div class="source">
				4615	<div class="source">
				4616	<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") ],
				4617	"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") ],
				4618	"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") ] }
				4619	</pre></div></div></li>
				4620	</ul></div></div>
				4621	<div class="section">
				4622	<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>
				4623	<div class="section">
				4624	<h3><a name="get-record-fields"></a>get-record-fields</h3>
				4625
				4626	<ul>
				4627
				4628	<li>
				4629	<p>Syntax:</p>
				4630
				4631	<div class="source">
				4632	<div class="source">
				4633	<pre>get-record-fields(record_expression)
				4634	</pre></div></div></li>
				4635
				4636	<li>
				4637	<p>Access the record field names, type and open status for a given record.</p></li>
				4638
				4639	<li>Arguments:
				4640
				4641	<ul>
				4642
				4643	<li><tt>record_expression</tt> : a record value.</li>
				4644	</ul></li>
				4645
				4646	<li>Return Value:
				4647
				4648	<ul>
				4649
				4650	<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>
				4651	</ul></li>
				4652
				4653	<li>
				4654	<p>Example:</p>
				4655
				4656	<div class="source">
				4657	<div class="source">
				4658	<pre>let $r1 := {"id": 1,
				4659	"project": "AsterixDB",
				4660	"address": {"city": "Irvine", "state": "CA"},
				4661	"related": ["Hivestrix", "Preglix", "Apache VXQuery"] }
				4662	return get-record-fields($r1)
				4663	</pre></div></div></li>
				4664
				4665	<li>
				4666	<p>The expected result is:</p>
				4667
				4668	<div class="source">
				4669	<div class="source">
				4670	<pre>[ { "field-name": "id", "field-type": "INT64", "is-open": false },
				4671	{ "field-name": "project", "field-type": "STRING", "is-open": false },
				4672	{ "field-name": "address", "field-type": "RECORD", "is-open": false, "nested": [
				4673	{ "field-name": "city", "field-type": "STRING", "is-open": false },
				4674	{ "field-name": "state", "field-type": "STRING", "is-open": false } ] },
				4675	{ "field-name": "related", "field-type": "ORDEREDLIST", "is-open": false, "list": [
				4676	{ "field-type": "STRING" },
				4677	{ "field-type": "STRING" },
				4678	{ "field-type": "STRING" } ] } ]
				4679	</pre></div></div></li>
				4680	</ul>
				4681	<p>]</p></div>
				4682	<div class="section">
				4683	<h3><a name="get-record-field-value"></a>get-record-field-value</h3>
				4684
				4685	<ul>
				4686
				4687	<li>
				4688	<p>Syntax:</p>
				4689
				4690	<div class="source">
				4691	<div class="source">
				4692	<pre>get-record-field-value(record_expression, string_expression)
				4693	</pre></div></div></li>
				4694
				4695	<li>
				4696	<p>Access the field name given in the <tt>string_expression</tt> from the <tt>record_expression</tt>.</p></li>
				4697
				4698	<li>Arguments:
				4699
				4700	<ul>
				4701
				4702	<li><tt>record_expression</tt> : A <tt>record</tt> value.</li>
				4703
				4704	<li><tt>string_expression</tt> : A <tt>string</tt> representing the top level field name.</li>
				4705	</ul></li>
				4706
				4707	<li>Return Value:
				4708
				4709	<ul>
				4710
				4711	<li>An <tt>any</tt> value saved in the designated field of the record.</li>
				4712	</ul></li>
				4713
				4714	<li>
				4715	<p>Example:</p>
				4716
				4717	<div class="source">
				4718	<div class="source">
				4719	<pre>let $r1 := {"id": 1,
				4720	"project": "AsterixDB",
				4721	"address": {"city": "Irvine", "state": "CA"},
				4722	"related": ["Hivestrix", "Preglix", "Apache VXQuery"] }
				4723	return get-record-field-value($r1, "project")
				4724	</pre></div></div></li>
				4725
				4726	<li>
				4727	<p>The expected result is:</p>
				4728
				4729	<div class="source">
				4730	<div class="source">
				4731	<pre>"AsterixDB"
				4732	</pre></div></div></li>
				4733	</ul></div></div>
				4734	<div class="section">
				4735	<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>
				4736	<div class="section">
				4737	<h3><a name="create-uuid"></a>create-uuid</h3>
				4738
				4739	<ul>
				4740
				4741	<li>
				4742	<p>Syntax:</p>
				4743
				4744	<div class="source">
				4745	<div class="source">
				4746	<pre>create-uuid()
				4747	</pre></div></div></li>
				4748
				4749	<li>
				4750	<p>Generates a <tt>uuid</tt>.</p></li>
				4751
				4752	<li>Arguments:
				4753
				4754	<ul>
				4755
				4756	<li>none</li>
				4757	</ul></li>
				4758
				4759	<li>Return Value:
				4760
				4761	<ul>
				4762
				4763	<li>A generated <tt>uuid</tt>.</li>
				4764	</ul></li>
				4765	</ul></div>
				4766	<div class="section">
				4767	<h3><a name="is-null"></a>is-null</h3>
				4768
				4769	<ul>
				4770
				4771	<li>
				4772	<p>Syntax:</p>
				4773
				4774	<div class="source">
				4775	<div class="source">
				4776	<pre>is-null(var)
				4777	</pre></div></div></li>
				4778
				4779	<li>
				4780	<p>Checks whether the given variable is a <tt>null</tt> value.</p></li>
				4781
				4782	<li>Arguments:
				4783
				4784	<ul>
				4785
				4786	<li><tt>var</tt> : A variable (any type is allowed).</li>
				4787	</ul></li>
				4788
				4789	<li>Return Value:
				4790
				4791	<ul>
				4792
				4793	<li>A <tt>boolean</tt> on whether the variable is a <tt>null</tt> or not.</li>
				4794	</ul></li>
				4795
				4796	<li>
				4797	<p>Example:</p>
				4798
				4799	<div class="source">
				4800	<div class="source">
				4801	<pre>for $m in ['hello', 'world', null]
				4802	where not(is-null($m))
				4803	return $m
				4804	</pre></div></div></li>
				4805	</ul>
				4806
				4807	<ul>
				4808
				4809	<li>
				4810	<p>The expected result is:</p>
				4811
				4812	<div class="source">
				4813	<div class="source">
				4814	<pre>"hello"
				4815	"world"
				4816	</pre></div></div></li>
				4817	</ul></div>
				4818	<div class="section">
				4819	<h3><a name="is-system-null"></a>is-system-null</h3>
				4820
				4821	<ul>
				4822
				4823	<li>
				4824	<p>Syntax:</p>
				4825
				4826	<div class="source">
				4827	<div class="source">
				4828	<pre>is-system-null(var)
				4829	</pre></div></div></li>
				4830
				4831	<li>
				4832	<p>Checks whether the given variable is a <tt>system null</tt> value.</p></li>
				4833
				4834	<li>Arguments:
				4835
				4836	<ul>
				4837
				4838	<li><tt>var</tt> : A variable (any type is allowed).</li>
				4839	</ul></li>
				4840
				4841	<li>Return Value:
				4842
				4843	<ul>
				4844
				4845	<li>A <tt>boolean</tt> on whether the variable is a <tt>system null</tt> or not.</li>
				4846	</ul></li>
				4847	</ul></div>
				4848	<div class="section">
				4849	<h3><a name="len"></a>len</h3>
				4850
				4851	<ul>
				4852
				4853	<li>
				4854	<p>Syntax:</p>
				4855	<p>len(list_expression)</p></li>
				4856
				4857	<li>
				4858	<p>Returns the length of the list list_expression.</p></li>
				4859
				4860	<li>Arguments:
				4861
				4862	<ul>
				4863
				4864	<li><tt>list_expression</tt> : An <tt>OrderedList</tt>, <tt>UnorderedList</tt> or <tt>null</tt>, represents the list need to be checked.</li>
				4865	</ul></li>
				4866
				4867	<li>Return Value:
				4868
				4869	<ul>
				4870
				4871	<li>An <tt>Int32</tt> that represents the length of list_expression.</li>
				4872	</ul></li>
				4873
				4874	<li>
				4875	<p>Example:</p>
				4876
				4877	<div class="source">
				4878	<div class="source">
				4879	<pre>use dataverse TinySocial;
				4880
				4881	let $l := ["ASTERIX", "Hyracks"]
				4882	return len($l)
				4883	</pre></div></div></li>
				4884	</ul>
				4885
				4886	<ul>
				4887
				4888	<li>
				4889	<p>The expected result is:</p>
				4890
				4891	<div class="source">
				4892	<div class="source">
				4893	<pre>2
				4894	</pre></div></div></li>
				4895	</ul></div>
				4896	<div class="section">
				4897	<h3><a name="not"></a>not</h3>
				4898
				4899	<ul>
				4900
				4901	<li>
				4902	<p>Syntax:</p>
				4903
				4904	<div class="source">
				4905	<div class="source">
				4906	<pre>not(var)
				4907	</pre></div></div></li>
				4908
				4909	<li>
				4910	<p>Inverts a <tt>boolean</tt> value</p></li>
				4911
				4912	<li>Arguments:
				4913
				4914	<ul>
				4915
				4916	<li><tt>var</tt> : A <tt>boolean</tt> (or <tt>null</tt>)</li>
				4917	</ul></li>
				4918
				4919	<li>Return Value:
				4920
				4921	<ul>
				4922
				4923	<li>A <tt>boolean</tt>, the inverse of <tt>var</tt>. returns <tt>null</tt> if <tt>var</tt> is null</li>
				4924	</ul></li>
				4925
				4926	<li>
				4927	<p>Example:</p>
				4928
				4929	<div class="source">
				4930	<div class="source">
				4931	<pre>for $m in ['hello', 'world', null]
				4932	where not(is-null($m))
				4933	return $m
				4934	</pre></div></div></li>
				4935
				4936	<li>
				4937	<p>The expected result is:</p>
				4938
				4939	<div class="source">
				4940	<div class="source">
				4941	<pre>"hello"
				4942	"world"
				4943	</pre></div></div></li>
				4944	</ul></div>
				4945	<div class="section">
				4946	<h3><a name="range"></a>range</h3>
				4947
				4948	<ul>
				4949
				4950	<li>
				4951	<p>Syntax:</p>
				4952
				4953	<div class="source">
				4954	<div class="source">
				4955	<pre>range(start_numeric_expression, end_numeric_expression)
				4956	</pre></div></div></li>
				4957
				4958	<li>
				4959	<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>
				4960
				4961	<li>Arguments:</li>
				4962
				4963	<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>
				4964
				4965	<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>
				4966
				4967	<li>Return Value:
				4968
				4969	<ul>
				4970
				4971	<li>A generated <tt>uuid</tt>.</li>
				4972	</ul></li>
				4973
				4974	<li>
				4975	<p>Example:</p>
				4976
				4977	<div class="source">
				4978	<div class="source">
				4979	<pre>for $i in range(0, 3)
				4980	return $i;
				4981	</pre></div></div></li>
				4982
				4983	<li>
				4984	<p>The expected result is:</p>
				4985
				4986	<div class="source">
				4987	<div class="source">
				4988	<pre>[ 0
				4989	, 1
				4990	, 2
				4991	, 3
				4992	]
				4993	</pre></div></div></li>
				4994	</ul></div>
				4995	<div class="section">
				4996	<h3><a name="switch-case"></a>switch-case</h3>
				4997
				4998	<ul>
				4999
				5000	<li>
				5001	<p>Syntax:</p>
				5002
				5003	<div class="source">
				5004	<div class="source">
				5005	<pre>switch-case(condition,
				5006	case1, case1-result,
				5007	case2, case2-result,
				5008	...,
				5009	default, default-result
				5010	)
				5011	</pre></div></div></li>
				5012
				5013	<li>
				5014	<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>
				5015
				5016	<li>Arguments:
				5017
				5018	<ul>
				5019
				5020	<li><tt>condition</tt>: A variable (any type is allowed).</li>
				5021
				5022	<li><tt>caseI/default</tt>: A variable (any type is allowed).</li>
				5023
				5024	<li><tt>caseI/default-result</tt>: A variable (any type is allowed).</li>
				5025	</ul></li>
				5026
				5027	<li>Return Value:
				5028
				5029	<ul>
				5030
				5031	<li>Returns <tt>caseI-result</tt> if <tt>condition</tt> matches <tt>caseI</tt>, otherwise <tt>default-result</tt>.</li>
				5032	</ul></li>
				5033
				5034	<li>
				5035	<p>Example 1:</p>
				5036
				5037	<div class="source">
				5038	<div class="source">
				5039	<pre>switch-case("a",
				5040	"a", 0,
				5041	"x", 1,
				5042	"y", 2,
				5043	"z", 3
				5044	)
				5045	</pre></div></div></li>
				5046	</ul>
				5047
				5048	<ul>
				5049
				5050	<li>
				5051	<p>The expected result is:</p>
				5052
				5053	<div class="source">
				5054	<div class="source">
				5055	<pre>0
				5056	</pre></div></div></li>
				5057
				5058	<li>
				5059	<p>Example 2:</p>
				5060
				5061	<div class="source">
				5062	<div class="source">
				5063	<pre>switch-case("a",
				5064	"x", 1,
				5065	"y", 2,
				5066	"z", 3
				5067	)
				5068	</pre></div></div></li>
				5069
				5070	<li>
				5071	<p>The expected result is:</p>
				5072
				5073	<div class="source">
				5074	<div class="source">
				5075	<pre>3
				5076	</pre></div></div></li>
				5077	</ul></div></div>
				5078	</div>
				5079	</div>
				5080	</div>
				5081
				5082	<hr/>
				5083
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				5086	<div class="row span12">Copyright © 2016
				5087	<a href="http://www.apache.org/">The Apache Software Foundation</a>.
				5088	All Rights Reserved.
				5089
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