sql server in 子查询

最新推荐文章于 2024-11-24 23:44:06 发布

XIAOTIANTIAN138

最新推荐文章于 2024-11-24 23:44:06 发布

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文章标签： SQL Server SQL

本文介绍了三种SQL查询技巧：使用exists方法、内连接及表关联来筛选特定国家的员工地址信息。

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期望是这种查询
select * From Empoylee Where
(Address1,Address2) in
(Select Address1,Address2
From EmpoyleeAdresses
Where Country = 'Canada') 这种查不出来你可以以下方法
1 exists 方法
select a.* From Empoylee a
Where exists
(select 'A' from EmpoyleeAdresses b
Where
b.Country = 'Canada'
and a.Address1=b.Address1
and a.Address2=b.Address2
)
2 用内连接
select *
From
Empoylee
inner join EmpoyleeAdresses
on
Empoylee.Address1=EmpoyleeAdresses.Address1
and
Empoylee.Address2=EmpoyleeAdresses.Address2
Where
EmpoyleeAdresses.Country = 'Canada')

select *
from
Empoylee em
inner join EmpoyleeAdresses emA
on
em.Address1=emA.Address1
and
em.Address2=emA.Address2
and
emA.Country = 'Canada'

3 表关联

select a.*
From
Empoylee a ,
(Select
Address1,Address2 From EmpoyleeAdresses
Where
Country = 'Canada') b
Where
a.Address1=b.Address1
and
a.Address2 = b.Address2