Symfony2 - subquery within a join error - mysql

Question

I would like to use a subquery inside a join, however Symfony2 throws the following error:
Here is my failed attempt:
$query = $em->createQuery(
'SELECT
sc.id AS id,
u.id AS userId,
u.username AS username,
sc_count.upvotes
FROM
myBundle:SuggestedCar sc
INNER JOIN myBundle:User u WITH sc.user_id = u.id
INNER JOIN ( SELECT sc1.user_id, COUNT(sc1.id) AS upvotes
FROM myBundle:SuggestedCar sc1
GROUP BY sc1.user_id
) sc_count WITH u.id = sc_count.user_id'
);
Basically I'm just joining 3 tables and the third one has a count. The query worked when executing it inside the database.
How would it be possible to use a SELECT statement inside a join? Is it a good idea to use raw SQL at this point?

Answer 1

The $em->createQuery() function is expecting DQL as the parameter, not SQL. If you want to execute a raw SQL statement, the syntax is different. You can do it like this:
$sql = "SELECT * FROM my_table";
$em = $this->getDoctrine()->getManager();
$stmt = $em->getConnection()->prepare($sql);
$stmt->execute();
$result = $stmt->fetchAll();
for more on DQL or querying for objects, see Querying for Object. The biggest difference is DQL will return an object (based on your entity classes in Symfony). The method I posted above will just give you a PDO result. So if you execute raw SQL, don't expect to be able to use the result as an object.
If you want to use raw SQL and still have the result mapped to an object, you can look at the doctrine docs about Result set mapping. In my opinion, this is more work than necessary.