Doctrine本机查询 - 实体结果问题

Question

我有以下内容：

$sql = "SELECT s.userid
                FROM  app_instagram_shop s 
                WHERE  s.expirydate IS NOT NULL 
                AND  s.expirydate >= NOW() 
                AND  s.isLocked = false
                AND  s.deletedAt IS NULL 
                ORDER BY  s.updated ASC
                LIMIT 5
                ";

        $rsm = new \Doctrine\ORM\Query\ResultSetMappingBuilder($this->_em); 
        $rsm->addEntityResult('AppMainBundle:InstagramShop', 's');
        $rsm->addFieldResult('s', 'userid', 'userid');
        return $this->_em->createNativeQuery($sql, $rsm)->getResult();

知道为什么这不起作用？我得到了以下错误：

Undefined index: id in /var/www/App/vendor/doctrine/orm/lib/Doctrine/ORM/UnitOfWork.php on line 2432