title: Generate form symfony2 with others entities and QueryBuilder
body: <p>I'm wondering how I can generate a form asking the user which country he's living in.</p>
  
  <p>Currently here is my code in my AnnonceType.php (form) </p>
  
  <pre><code>$builder
  -&gt;add('idPa', 'entity', array( 
              'label' =&gt; 'Pays',
              'class' =&gt; 'nftAnnonceBundle:Pays',
              'query_builder' =&gt; function(EntityRepository $er)
              {    
                  return                
                  $er-&gt;createQueryBuilder('p')
                  -&gt;select('nomPa')
                  -&gt;from('nftAnnonceBundle:Pays', 'p');                    
              },
              'property' =&gt; 'nom_pa'
           ))
  </code></pre>
  
  <p>I'm looking for custom query because i have a geom data column in my database and my application is crashing if doctrine does load it ... </p>
  
  <p>To be clear i'd just like to create a select fields asking the label_country (from my database) to the user and having as value the id_country.
  I tried to overwrite the select fields from createQueryBuilder() with a -> select but doens't seems to work. </p>
  
  <pre><code>[Semantical Error] line 0, col 72 near 'p': Error: 'p' is already defined.
  </code></pre>
  
  <p>Thanks for your help</p>