title: PHP using Doctrine Criteria obj, no groupBy function
body: <p>It seems that there is no <code>groupBy</code> method inside <a href="http://doctrine-orm.readthedocs.org/projects/doctrine-orm/en/latest/reference/working-with-associations.html#filtering-collections" rel="nofollow noreferrer">the Doctrine 2 <code>Criteria</code> class</a>. How to add one to my <code>Criteria</code> object?</p>
  
  <p><a href="https://i.stack.imgur.com/owMPU.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/owMPU.png" alt="enter image description here"></a></p>