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POSPARQL get more than one subitem
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  1. POSPARQL get more than one subitem
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    copied!<p>I query an API with a simple SPARQL query:</p> <pre><code>PREFIX ... SELECT DISTINCT * WHERE { ?item dct:date ?date . ?item dct:title ?title . ?item rdfs:info ?info . } </code></pre> <p>And this returns me an xml </p> <pre><code>&lt;results&gt; &lt;result&gt; &lt;binding name='title'&gt; &lt;literal&gt;titletitle&lt;/literal&gt; &lt;/binding&gt; &lt;binding name='info'&gt; &lt;uri&gt;link&lt;/uri&gt; &lt;/binding&gt; &lt;binding name='date'&gt; &lt;literal datatype='http://www.w3.org/2001/XMLSchema#dateTime'&gt;2012-12-21T02:26:00+00:00&lt;/literal&gt; &lt;/binding&gt; &lt;binding name='item'&gt; &lt;uri&gt;link&lt;/uri&gt; &lt;/binding&gt; &lt;/result&gt; ... &lt;/results&gt; </code></pre> <p>But the problem is: I know, that there are more than one links of rdfs:info matched to this item. How can I query such that I get </p> <pre><code>... &lt;binding name='info'&gt; &lt;uri&gt;link1&lt;/uri&gt; &lt;/binding&gt; &lt;binding name='info'&gt; &lt;uri&gt;link2&lt;/uri&gt; &lt;/binding&gt; &lt;binding name='info'&gt; &lt;uri&gt;link3&lt;/uri&gt; &lt;/binding&gt; ... </code></pre> <p>? Is this simple, or do I need a subquery or some strange <code>UNION</code>? If I just try</p> <pre><code> PREFIX ... SELECT DISTINCT * WHERE { ?item dct:date ?date . ?item dct:title ?title . OPTIONAL (?item rdfs:info ?info1 ). OPTIONAL (?item rdfs:info ?info2 ). } </code></pre> <p>that would return all possible permutations of the values of <code>?info1</code> and <code>?info2</code>. Plus, I don't know the number of info items.</p> <p>If I add <code>FILTER (?info1 != ?info2)</code>, I still get some permutations. I think from an algebraic point of view it would be possible to <code>FILTER (?info1 &lt; ?info2)</code>, to discard permutations. But how can I apply <code>&lt;</code> on uris? </p>
 

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