Doctrine\DBAL\Connection::createQueryBuilder PHP Method

    public function createQueryBuilder()
    {
        return new Query\QueryBuilder($this);
    }

 public function count()
 {
     $qb = $this->dbal->createQueryBuilder();
     $qb->select('count(*) c')->from('(' . $this->qb->getSQL() . ')', 'xxx');
     $row = $this->dbal->fetchAssoc($qb->getSQL());
     return $this->count = intval($row['c']);
 }