title: Join subquery with doctrine and Symfony 2
body: <p>I saw the begining of an answer in a post about Zend : <a href="https://stackoverflow.com/questions/34768821/join-subquery-with-doctrine-2-dbal/37726068#37726068">Join subquery with doctrine 2 DBAL</a>
  Unfortunately I can't manage it to work. I tried aimfeld soltuion like that:</p>
  
  <pre><code>$qbaudio = $em-&gt;createQueryBuilder();
      $subSelect = $qbaudio-&gt;select ('a.id_support id_support','sum(a.duration) dureeTotale','count(a) nbAudio')
          -&gt;from('MyBundle:AudioObject','a')
          -&gt;groupBy('a.id_support')
          -&gt;where('a.type = :audio_type')
          -&gt;getQuery();
      $qb = $em-&gt;createQueryBuilder();
      $qb-&gt;select('sp.ref1','sp.title1','count(i) nbImage','sp.nbSupportSaisi','sum(a.duration) dureeTotale','count(a) nbAudio','a.sampling')
        -&gt;from('MyBundle:Storage', 'st')
              -&gt;leftJoin('p.sides','si')
              -&gt;leftJoin('si.support','sp')
              -&gt;leftJoin('sp.images','i')
              -&gt;leftJoin('sp.audioObjects', sprintf('(%s)',$subSelect-&gt;getDQL()), 'a', 'ON sp.id = a.id_support')
              -&gt;groupBy('sp.id')
              -&gt;setParameter('audio_type', 'MP3')
  </code></pre>
  
  <p>Unfortunately I got this message :</p>
  
  <pre><code>Error: Expected end of string, got 'SELECT'
  </code></pre>
  
  <p>If it's possible with ZEnd, Why not with Symfony?
  Any idea? 
  Thanks</p>