title: 'where not in' query with doctrine query builder
body: <p>Im trying to reproduce this query:</p>
  
  <pre><code>SELECT * FROM `request_lines`
  where request_id not in(
  select requestLine_id from `asset_request_lines` where asset_id = 1 
  )
  </code></pre>
  
  <p>in doctrine query builder,
  I am stuck on the where request_id not in(select</p>
  
  <p>I currently have:</p>
  
  <pre><code>$linked = $em-&gt;createQueryBuilder()
          -&gt;select('rl')
          -&gt;from('MineMyBundle:MineRequestLine', 'rl')
          -&gt;where()
          -&gt;getQuery()
          -&gt;getResult();
  </code></pre>