title: Select where count of another table is zero
body: <p>I have two tables (<code>questions</code> and <code>answers</code>), and wish to select the rows from <code>questions</code> only when the corresponding count in <code>answers</code> is zero, in other words, when there are no answers which match <code>questionid</code>.</p>
  
  <p>My query so far is:</p>
  
  <pre><code>SELECT q.* , COUNT(a.id) FROM questions q LEFT OUTER JOIN answers a ON q.id = a.questionid WHERE COUNT(a.id)=0
  </code></pre>
  
  <p>I'm not sure if it's possible to do it like that, but it's not working. Any ideas?</p>
  
  <p>Thank you</p>