注意：未定义的索引：search_question_connect_id

Question

rsm = new ResultSetMapping;
        $rsm->addEntityResult('AccountClientBundle:SearchQuestionConnect', 'c');
        $rsm->addFieldResult('c', 'c_id', 'id');
        $rsm->addFieldResult('c', 'c_distance', 'distance');
        $rsm->addJoinedEntityResult('AccountClientBundle:SearchQuestionConnectPriceComment', 'sq', 'c', 'search_question_connect_id');
        $rsm->addFieldResult('sq', 'sq_id', 'id');
        $rsm->addMetaResult('sq', 'sq_search_question_connect_id', 'search_question_connect_id');

$q = $this->getEntityManager()->createNativeQuery("
              SELECT
              c.id AS c_id,
              c.distance AS c_distance,
              sq.id AS sq_id,
              sq.search_question_connect_id AS sq_search_question_connect_id
              FROM search_question_connects AS c
              JOIN (SELECT * FROM search_question_connect_price_comments ORDER BY created_at DESC) AS sq ON (sq.search_question_connect_id=c.id)
              WHERE
              c.search_id = {$searchId}
              AND c.status_bidder = 2
              GROUP BY c.id
              ORDER BY sq.created_at DESC
              ", $rsm);
        $r = $q->getResult();

我们收到以下错误：

  

注意：未定义的索引：search_question_connect_id

任何人都知道导致此通知的原因是什么？