title: Doctrine query builder : semantical error
body: <p>I have a table named "Annonce" that contains some informations about a post ; I would like to retrieve all the "type_bien" (it's a field) already registered in the database by a query. My table has the good field "type_bien", my Entity also.</p>
  
  <p>So I tryed : </p>
  
  <pre><code>$em = $this-&gt;get('doctrine')-&gt;getEntityManager();
  $query = $em-&gt;createQuery( 'SELECT DISTINCT type_bien FROM APNegociationBundle:Annonce' );
  </code></pre>
  
  <p>But I got a semantical error : </p>
  
  <pre><code>[Semantical Error] line 0, col 16 near 'type_bien FROM': Error: 'type_bien' is not defined.
  </code></pre>
  
  <p>Is there something wrong with my query ?</p>