Translating sql query into Doctrine/dql

Question

This is the query I want:

SELECT * FROM (SELECT * FROM counter ORDER BY id DESC) AS x GROUP BY campaign_id

but I can´t find a way to express this in my Symfony application. What is the correct way to use subqueries like this one in Doctrine?

This one:

$query = $em->createQuery('SELECT c
        FROM InstacountInstacountBundle:Counter c
        GROUP BY c.campaign');  
    $counts = $query->getResult();

is working fine, but I want only the latest records in my group. Thanks for any help!

Answer 1

SELECT x.* 
  FROM counter x
  JOIN 
     ( SELECT campaign_id, MAX(id) max_id FROM counter GROUP BY campaign_id ) y
    ON y.campaign_id = x.campaign_id
   AND y.max_id = x.id;