Convert SQL into Doctrine 2 QueryBuilder - symfony

Question

I need help to convert a valid SQL query into createQueryBuilder. The problem I have is I don't know how to LEFT JOIN on a SELECT in the createQueryBuilder.
SELECT username, count(c.user_owner_id) as num_contact, a_g.name as
group_name
FROM `oro_user` as u
INNER JOIN `oro_user_access_group` as u_g on u.id=u_g.user_id
INNER JOIN `oro_access_group` as a_g on u_g.group_id=a_g.id
LEFT JOIN
(SELECT cc.user_owner_id
FROM `orocrm_contact` as cc
INNER JOIN`orocrm_contact_to_contact_grp` as cc_g on cc_g.contact_id=cc.id
INNER JOIN `orocrm_contact_group`
as c_g on cc_g.contact_group_id=c_g.id
WHERE c_g.label='New One' and cc.semester_contacted='2017A')
as c on u.id=c.user_owner_id
WHERE a_g.name='Full-timer' and u.enabled = 1 and u.gender='male'
GROUP BY u.id
ORDER BY num_contact
I have two queries below, I want user to LEFT JOIN the results from contact
$user = $this->em->getRepository('OroUserBundle:User')->createQueryBuilder('u')
->select('u.username')
->innerJoin('u.groups','g')
->andWhere('g.name = :group')
->setParameter('group', 'Full-timer')
->getQuery();
$contacts = $this->em->getRepository('OroContactBundle:Contact')->createQueryBuilder('c')
->select('c')
->innerJoin('c.groups','g')
->andWhere('g.label = :group')
->andWhere('c.semester_contacted = :sem')
->setParameter('group', 'New One')
->setParameter('sem', '2017A')
->setMaxResults(1)
->getQuery();

Answer 1

This is a pretty complex queries and since the ORM QueryBuilder works closer to your entities than the database I'm not sure if you can just "dump" the DQL into a ->join(). The good news with the DBAL QueryBuilder that works:
$dbalQueryBuilder
->from('user_table as u')
...
->join('u', '('.$otherDbalQueryBuilder->getSQL().')', 'c')
This is from memory so it might be a little different, but something like that.
With that you can get all the fields you require, but you won't get any entities. Luckily Doctrine provides ways to build entities from Native SQL using ResultSetMapping.
$userWithContacts = $entityManager->createNativeQuery(
$dbalQueryBuilder->getSQL(),
$yourResultSetMapping
);
I know this is will require more code and is probably not as nice as just using the ORM QueryBuilder, but I find it oftentimes to be the best way to deal with existing queries that need to be ported to ORM somehow.