mysql-mySql多表查询，有中间表和外键关联
2020-11-09
来源：年旅网
select a.id,a.name,
sum(case when d.STATUS=0 then 1 else 0 end) as 待处理,
sum(case when d.STATUS=1 then 1 else 0 end) as 带跟进,
sum(case when d.STATUS=2 then 1 else 0 end) as 已结束,
sum(case when d.STATUS=3 then 1 else 0 end) as 已完成
from D d,A a
where a.id = d.Aid (d表的Aid和a表的id对应,但d表有多条数据的Aid=a.id)
group by a.id
select a.id,a.name as 处理人,c.name as 所属机构
from A a,B b,C c
where a.id = b.Aid and c.id = b.Cid (B表是中间表，只存放a表的ID和c表的ID)
就是把这两个sql语句写在一个里面
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