网络营销导向的网站建设,福州网站建设发布,淘宝运营学习,中华衣柜网期望效果#xff1a;#xff08;我是拿到一对关系去另一表中的一对关系去对比#xff09;select * From Empoylee Where
(Address1,Address2) in
(Select Address1,Address2
From EmpoyleeAdresses
Where Country Canada)以上无法实现用这种方案也可以实现 不过速度很慢的s… 期望效果我是拿到一对关系去另一表中的一对关系去对比select * From Empoylee Where
(Address1,Address2) in
(Select Address1,Address2
From EmpoyleeAdresses
Where Country Canada)以上无法实现用这种方案也可以实现 不过速度很慢的select * from (select (zcbm ||,||fwbm) as t from T_FWZC ) tt where t not in(select (zcbm ||,||fwbm) as c from T_ZC_FC_GX)解决方案1用exists判断select a.* From Empoylee a
Where exists(select A from EmpoyleeAdresses bWhereb.Country Canadaand a.Address1b.Address1and a.Address2b.Address2)解决方案2用inner join内链接select *
From
Empoylee
inner join EmpoyleeAdresses
on
Empoylee.Address1EmpoyleeAdresses.Address1
and
Empoylee.Address2EmpoyleeAdresses.Address2
Where
EmpoyleeAdresses.Country Canada)select *
from
Empoylee em
inner join EmpoyleeAdresses emA
on
em.Address1emA.Address1
and
em.Address2emA.Address2
and
emA.Country Canada解决方案3表关联select a.*
From
Empoylee a ,(SelectAddress1,Address2 From EmpoyleeAdresses WhereCountry Canada) b
Where
a.Address1b.Address1
and
a.Address2 b.Address2主观感觉方案1更快一些客观上还没在查询分析器里用显示执行计划看哪种写法效率高些. 如果是Delete语句写法如下Delete From Empoylee
Where exists(select A from EmpoyleeAdresses bWhereb.Country Canadaand Empoylee.Address1b.Address1and Empoylee.Address2b.Address2)
注意Delete from 后的表不能用别名
