Doctrine2 QB – how to select entities where OnetoOne entity doesn't exists - php

Question

I have two entities:
class User extends BaseEntity {
/**
* #ORM\OneToOne(targetEntity="Profile", mappedBy="user", cascade={"persist", "remove"})
* #var Profile
*/
protected $profile;
}
class Profile extends BaseEntity {
/**
* #ORM\OneToOne(targetEntity="User", inversedBy="profile", cascade={"persist"})
* #ORM\JoinColumn(name="user_id", referencedColumnName="id", onDelete="CASCADE")
* #var User
*/
protected $user;
}
What I'm trying to do is to SELECT only users who don't have any profile (so there's no profile row with user_id=:user_id in profiles table). However, I have no idea how to make my QueryBuilder.
First, I tried something simple like
//u as user
$query = $this->er->createQueryBuilder('u');
$query
->join('u.profile', 'p')
->where('u.profile = 1');
But that returns A single-valued association path expression to an inverse side is not supported in DQL queries. Use an explicit join instead. so I suppose there's something wrong with my relationship? I tried to switch join() for leftJoin() but it didn't help either...
So what's up with this error and how to make proper condition with where() to tell Doctrine I want only users where there's no profile?

Answer 1

Here is how I was able to do it. Basically I had Domain & Hosting entities and I wanted to select Domains that had no Hosting attached to them in a one to one relationship.
$er->createQueryBuilder('d')
->leftJoin('d.hosting', 'h')
->where('h.id is NULL');
Credits for this solution goes to this Answer
Hope it works for you since our situations are almost identical.

Answer 2

Just check for null as value of profile
//u as user
$query = $this->er->createQueryBuilder('u');
$query
->where('u.profile is NULL');

Answer 3

Try to use repositories, example for UserRepository:
$qb = $this->createQueryBuilder('u');
$e = $qb->expr();
$qb->leftJoin('u.profile', 'p')
->where($e->isNull('p.id'))
Raw query will look like this:
SELECT * FROM users AS u LEFT JOIN u.profile AS p WHERE p.id IS NULL;