Symfony : Create a queryBuilder between two entities without mapping - doctrine-orm

Question

I have two entities (there is no relation between the two entities): A: Relation and B: Post.
I get every post from the current user to display them on the homepage with this request:
public function getPostsCurrentUser($currentUser)
{
$qb = $this->createQueryBuilder('p');
$qb->where('p.member = :member')
->setParameters(['member' => $currentUser])
->orderBy('p.created', 'DESC');
return $qb->getQuery()->getResult();
}
In the example "A: Relation" the user 2 follow the user 1. When a user follow an other user, I would like to also display on the homepage every post of users that the current user are following.
I don't see how to create this request. Can anybody help me ?
Thanks

Answer 1

In the sense of http://sqlfiddle.com/#!9/c5a0bf/2, I would suggest something like the following which uses a subquery to select the ids of all followed users:
class PostRepository {
public function getPostsOfUser($id) {
$query = $this->getEntityManager()->createQuery(
"SELECT p.content
FROM AppBundle:Post p
WHERE p.member = :id
OR p.memberId IN (
SELECT r.friend
FROM AppBundle:Relation r
WHERE r.user = :id
)
ORDER BY p.created DESC"
);
return $query->setParameter('id', $id)
->getResult();
}
}