title: ORACLE DISTINCT inside a function
body: <p>I am trying to use the following on oracle 11g:</p>
  
  <pre><code>select sum(ora_hash(distinct attribute) from table;
  </code></pre>
  
  <p>This gives me the error:ORA-00936: "missing expression"</p>
  
  <p>I was expecting this to work, as for example
      sum(distinct attribute) from table;
  works fine.</p>
  
  <p>Any advice?</p>