Mysql查询(按顺序)非常慢
当我从另一个表使用ORDER BY时,它的工作速度非常慢。如何进行查询Mysql查询(按顺序)非常慢,mysql,Mysql,当我从另一个表使用ORDER BY时,它的工作速度非常慢。如何进行查询 SELECT u.*, (SELECT COUNT(id) FROM operations o WHERE o.userId=u.userId and o.status=1) as countOperations FROM users u ORDER BY countOperations 您的查询格式不正确。请尝试以下查询: select col1, col2, ..., coln, count(id) countOper
SELECT u.*, (SELECT COUNT(id) FROM operations o WHERE o.userId=u.userId and o.status=1) as countOperations FROM users u ORDER BY countOperations
您的查询格式不正确。请尝试以下查询:
select col1, col2, ..., coln, count(id) countOperations, SUM(o.sumRUB) sumRUB
from users u
inner join operations o
on o.userId=u.userId and o.status=1
group by col1, col2, ..., coln
ORDER BY countOperations
您可能还需要对operationsuserId、status进行索引,并且可能不需要对userscol1、col2、…、coln进行索引您需要为使用过的表提供表创建语句,并解释查询结果。那么,如果是2子查询?选择u.*,从操作o中选择COUNTid,其中o.userId=u.userId和o.status=1作为countOperations,从操作o中选择SUMo.sumRUB,其中o.userId=u.userId和o.status=1作为用户u ORDER BY countOperations的sumOp