public function deleteUserQuery($userId)
    {
        $qb = $this->createQueryBuilder();
        $qb->delete($this->getTableName());

        if (is_numeric($userId)) {
            $qb->where('id = :userId');
        } else {
            $qb->where('username = :userId')->orWhere('email = :userId');
        }
        $qb->setParameter('userId', $userId);

        return $qb;
    }