SQLServer数据集合的交、并、差集运算

SQLServer2005通过intersect,union,except和三个关键字对应交、并、差三种集合运算。

他们的对应关系可以参考下面图示

相关测试实例如下：

use tempdb
go

if
(object_id
('t1'
) is
not
null
) drop
table
t1

if
(object_id
('t2'
) is
not
null
) drop
table
t2

go

create
table
t1
(a
int
)
insert
into
t1
select

union
select

union
select

create
table
t2
(a
int
)
insert
into
t2
select

union
select

union
select

go

select
*
from
t1
union
select
*
from
t2

go

/* 求表并集

5*/

select
*
from
t1
union
all
  select
*
from
t2

go

/*求表并集不过滤重复

5*/

select
*
from
t1
except
select
*
from
t2

go

/*求t1对t2的差集

2*/

select
*
from
t1
intersect
select
*
from
t2

go

/*求t1对t2的交集

3*/