title: Doctrine query builder with join returns array of entities instead of grouped results
body: <p>I have some problems with Doctrine. Im trying to do a leftJoin, following this question: <a href="https://stackoverflow.com/questions/15087933/how-to-do-left-join-in-doctrine">How to do left join in Doctrine?</a></p>
  
  <p>Here is my query:</p>
  
  <pre><code>$qb = $this-&gt;getEntityManager()-&gt;createQueryBuilder();
      $qb
          -&gt;select('a', 'u')
          -&gt;from('Application\Entity\Event', 'a')
          -&gt;leftJoin(
              'Application\Entity\Venue',
              'u',
              \Doctrine\ORM\Query\Expr\Join::WITH,
              'a.venue_id = u.id'
          )
          -&gt;orderBy('a.event_datetime', 'DESC');
  
      var_dump($qb-&gt;getQuery()-&gt;getResult());
  </code></pre>
  
  <p>And here are the results:</p>
  
  <pre><code>array (size=4)
  0 =&gt; 
  object(Application\Entity\Event)[483]
    protected 'id' =&gt; int 8
    protected 'artist_id' =&gt; int 4
    protected 'venue_id' =&gt; int 1246
    protected 'name' =&gt; string 'Vlasta Redl' (length=11)
  1 =&gt; 
  object(Application\Entity\Venue)[477]
    protected 'id' =&gt; int 1246
    protected 'name' =&gt; string 'Malostranská beseda' (length=20)
    ...
  2 =&gt; 
  object(Application\Entity\Event)[468]
    protected 'id' =&gt; int 7
    protected 'artist_id' =&gt; int 3
    protected 'venue_id' =&gt; int 761
    protected 'name' =&gt; string 'Positive Mind' (length=13)
  
  3 =&gt; 
  object(Application\Entity\Venue)[485]
    protected 'id' =&gt; int 761
    protected 'name' =&gt; string 'Divadlo pod lampou' (length=18)
    ....
  </code></pre>
  
  <p>This is an array of different objects. Events and Venues.</p>
  
  <p>But I'm expecting such result:</p>
  
  <pre><code>array(
      array(
          0 =&gt; Event
          1 =&gt; Venue,
      ),
      array(
          0 =&gt; Event
          1 =&gt; Venue,
      ),
      // ...
  )
  </code></pre>
  
  <p>What am I doing wrong?</p>