title: sparql: how to avoid visited subject
body: <p>and I am trying to write SPARQL query to find distinct object.</p>
  
  <p>here is the dataset:</p>
  
  <pre><code>&lt;https://permid.org/1-36436064275&gt; &lt;http://www.w3.org/1999/02/22-rdf-syntax-ns#type&gt; &lt;https://permid.org/1-34414203048&gt; .
  
  &lt;https://permid.org/1-34414203048&gt; &lt;http://permid.org/ontology/person/hasTenureInOrganization&gt; &lt;https://permid.org/1-36436064275&gt; .
  </code></pre>
  
  <p>my sparql query is like this:</p>
  
  <pre><code>select distinct ?n where {
  
        &lt;https://permid.org/1-36436064275&gt; ?a ?b .
        ?b ?c ?d . 
        ?d ?e ?n .                     
  }
  </code></pre>
  
  <p>From the dataset, "?d" is <a href="https://permid.org/1-36436064275" rel="nofollow noreferrer">https://permid.org/1-36436064275</a>, which is the visited subject. I want to skip visited subject, so that "?d" is empty, thus "?n" is also empty. </p>