title: MYSQL select mutual friends
body: <p>My 'friends' table has the following columns: id, userID, userID2, state</p>
  
  <p>userID and userID2 don't have a specific order of being put into the database. </p>
  
  <p>I currently use this query to find a users friends:</p>
  
  <pre><code>$quer = mysql_query("
  SELECT CASE WHEN userID=$id THEN userID2 ELSE userID END AS friendID 
  FROM friends WHERE userID=$id OR userID2=$id");
  </code></pre>
  
  <p>I have tried this however it doesn't work:</p>
  
  <pre><code>SELECT 
  CASE WHEN userID=$id OR userID=$session THEN userID2 
  ELSE userID END AS friendID  
  FROM friends WHERE (userID=$session OR userID2=$session) 
  AND (userID=$id OR userID2=$id) AND friendID!=$session
  </code></pre>
  
  <p>also it shouldn't return the row if friendID=$session (which i have added to my second query)</p>
  
  <p><strong>EDIT</strong>:
  I want to return as friendID rows that $id and $session have in common. I'm not exactly sure why it isn't working.</p>