title: How to Implement UNION query in symfony Prople
body: <p>I am using symfony v.1.4.6 (Propel) &amp; php 5.2.6 </p>
  
  <p>I got one challanging situation where i have to implement the bellow query into symfony Propel
  I googled it alot but i failed to find the perfect solution to implement UNION in propel</p>
  
  <pre><code>SELECT top 5000 filetable.sha2, finalhash.ihash FROM filetable (nolock)
  JOIN finalhash (nolock) ON (filetable.finalhash_id=finalhash.id)
  WHERE (
      finalhash.ihash ='1FDE08EACCC5B247026D1D3A71DDD3846E31095D3A852CCFCDF3B7EAC00FD6D1' 
  ) 
  UNION ALL
  SELECT top 5000 filetable.sha2, finalhash.ihash FROM filetable (nolock)
  LEFT JOIN finalhash (nolock) ON (filetable.finalhash_id=finalhash.ID)
  WHERE (
      filetable.sha2='1FDE08EACCC5B247026D1D3A71DDD3846E31095D3A852CCFCDF3B7EAC00FD6D1'
  ) 
  </code></pre>
  
  <p>Please guide me and give suggestion to implement above query in symfony Propel :/ </p>
  
  <p>Thanks for all of you!</p>