Question

rails中的这个查询没有结束。为什么？查询是：

    SELECT CONCAT(f.name, ' ', f.parent_names) AS FullName,
       stts.name AS 'Status',
       u.name AS Unit,
       city.name AS City,
       hus.mobile1 AS HusbandPhone,
       wife.mobile1 AS WifePhone,
       f.phone AS HomePhone,
       f.contact_initiation_date AS InitDate,
       fh.created_at AS StatusChangeDate,
       cmt.created_at AS CommentDate,
       cmt.comment AS LastComment,
       f.reconnection_date AS ReconnectionDate,
  (SELECT GROUP_CONCAT(t.name, ' ')
   FROM taggings tgs
   JOIN tags t ON tgs.tag_id = t.id
   WHERE tgs.taggable_type = 'family'
     AND tgs.taggable_id = f.id) AS HandlingStatus
FROM families f
JOIN categories stts ON f.family_status_cat_id = stts.id
JOIN units u ON f.unit_id = u.id
JOIN categories city ON f.main_city_cat_id = city.id
LEFT JOIN contacts hus ON f.husband_id = hus.id
LEFT JOIN contacts wife ON f.wife_id = wife.id
LEFT JOIN comments cmt ON f.id = cmt.commentable_id
AND cmt.created_at =
  (SELECT MAX(created_at)
   FROM comments
   WHERE commentable_id = f.id)
LEFT JOIN family_histories fh ON f.id = fh.family_id
AND fh.created_at =
  (SELECT MAX(created_at)
   FROM family_histories
   WHERE family_id = f.id
     AND family_history_cat_id = 1422)
AND fh.family_history_cat_id = 1422
WHERE 1=0
  OR (f.family_status_cat_id = 1422
      AND (  (SELECT MAX(_fh.created_at)
              FROM family_histories _fh
              WHERE _fh.family_history_cat_id = 1422
                AND _fh.family_id = f.id
                AND _fh.new_val LIKE '%1422%') BETWEEN '2010-03-10' AND '2011-03-02'))

我错过了什么吗？ Synatx是正确的，那么问题是什么？

Answer 1

我认为问题是你必须有很多子查询。它需要花费很多时间。

我的建议是将子查询中获得的一些信息存储在主表中。

另外，您可以尝试制作商店程序以加快流程。

祝你好运

mysql查询需要花费很多时间

1 个答案: