Problem z LEFT JOIN

Question

<?php

namespace TransportBundle\Repository;

/**
 * TransportRepository
 *
 * This class was generated by the Doctrine ORM. Add your own custom
 * repository methods below.
 */
class TransportRepository extends \Doctrine\ORM\EntityRepository
{
  public function findAll() {
    return $this->getEntityManager()
      ->createQuery('SELECT t FROM TransportBundle:Transport t ORDER BY t.id ASC')
      ->getResult();
  }

  public function findNotActivated() {
    return $this->getEntityManager()
      ->createQuery('SELECT t FROM TransportBundle:Transport t LEFT JOIN UserBundle:User u WITH t.damage = u.avatar WHERE t.userName = u.username')
      ->getResult();
  }
}

Chodzi mi o funkcję findNotActivated, chciałbym zrobić tak aby w obiekcie t zmieniło t.id na u.avatar a u.avatar ma pobierać z UserBundle:User od użytkownika gdzie u.username == t.userName

 

Impossible to access an attribute ("username") on a null variable in @App/base_layout.html.twig at line 68