title: How would I do MySQL count(*) in Doctrine2?
body: <p>I have the following Doctrine2 query:</p>
  
  <pre><code>$qb = $em-&gt;createQueryBuilder()
        -&gt;select('t.tag_text, COUNT(*) as num_tags')
        -&gt;from('CompanyWebsiteBundle:Tag2Post', 't2p')
        -&gt;innerJoin('t2p.tags', 't')
        -&gt;groupBy('t.tag_text')
  ;
  $tags = $qb-&gt;getQuery()-&gt;getResult();
  </code></pre>
  
  <p>When run I get the following error: </p>
  
  <pre><code>[Semantical Error] line 0, col 21 near '*) as num_tags': Error: '*' is not defined. 
  </code></pre>
  
  <p>How would I do MySQL count(*) in Doctrine2?</p>