title: SPARQL Restrict Number of Results for Specific Variable
body: <p>Suppose I want to look for some first degree neighbors of Berlin. I ask the following query:</p>
  <pre class="lang-sql prettyprint-override"><code>select ?s ?p where {
    ?s ?p dbr:Berlin.
  }
  </code></pre>
  <p>Is it possible to put a restriction on the return result, such that there are at most 5 results for each unique value of <code>?p</code>?</p>