title: How to create queries with subqueries in Symfony Doctrine
body: <p>I want to make this sql query in doctrine:</p>
  
  <pre class="lang-sql prettyprint-override"><code>SELECT * 
  FROM (
    (SELECT *, e1.stop_date as sort_date FROM `event` e1 WHERE ...) 
    UNION 
    (SELECT *, e2.start_date as sort_date FROM `event` e2 WHERE ...)
  ) e3 
  ORDER BY e3.sort_date 
  </code></pre>
  
  <p>And I want to result of symfony model connected to the event table, like using:</p>
  
  <pre><code>Doctrine_Core::getTable('Event')-&gt;createQuery('e')
  </code></pre>
  
  <p>Any ideas?</p>