Symfony2 Doctrine SQL object mapping on subselect - symfony

Question

I'm trying to use this query:
MySQL SELECT DISTINCT by highest value
SELECT
p.*
FROM
product p
INNER JOIN
( SELECT
magazine, MAX(onSale) AS latest
FROM
product
GROUP BY
magazine
) AS groupedp
ON groupedp.magazine = p.magazine
AND groupedp.latest = p.onSale ;
Within Symfony2 and DQL.
I have:
$query = $em->createQuery("SELECT p FROM MyBundle:Product p WHERE p.type = 'magazine' AND p.maglink IS NOT NULL OR (p.type = 'magazine' AND p.diglink IS NOT NULL) GROUP BY p.magazine ORDER BY p.onSale DESC");
Which works fine with and outputs objects but without the correct MAX(onSale)
Doing:
$query = $em->createQuery("SELECT p , MAX(p.onSale) FROM MyBundle:Product p WHERE p.type = 'magazine' AND p.maglink IS NOT NULL OR (p.type = 'magazine' AND p.diglink IS NOT NULL) GROUP BY p.magazine ORDER BY p.onSale DESC");
Results in non-objects being returned.
This:
$query = $em->createQuery("SELECT
p.*
FROM
MyBundle:Product p
INNER JOIN
( SELECT
p.magazine, MAX(onSale) AS p.latest
FROM
MyBundle:Product p
GROUP BY
p.magazine
) AS groupedp
ON groupedp.magazine = p.magazine
AND groupedp.latest = p.onSale ;");
Throws this error:
[Semantical Error] line 0, col 127 near 'SELECT
': Error: Identification Variable ( used in join path expression but was not defined before.
I assume due to this Symfony2 Doctrine query
How can I maintain my mapping while still being able to sort each item by onsale?

Answer 1

Have you considered splitting this into two queries:
First:
Run your query directly against the database connection, and return the IDs of the relevant rows, in the order you want. This separates your complex query from DQL.
Second:
Query the rows through Doctrine to get the full entities you want, based on the IDs/orders of the previous query.

Answer 2

This is a shot in the dark, but it seems fairly obvious. Your aliasing two tables to the same alias. Thus when your using p. in the join it thinks your working from the original definition of p from before the join, then you alias the join as p. Change the alias of the join (and the references to that table) so each alias is unique.