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
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
1
union
select
2
union
select
3
create
table
t2
(a
int
)
insert
into
t2
select
3
union
select
4
union
select
5
go
select
*
from
t1
union
select
*
from
t2
go
/* 求表并集
1
2
3
4
5*/
select
*
from
t1
union
all
select
*
from
t2
go
/*求表并集不过滤重复
1
2
3
3
4
5*/
select
*
from
t1
except
select
*
from
t2
go
/*求t1对t2的差集
1
2*/
select
*
from
t1
intersect
select
*
from
t2
go
/*求t1对t2的交集
3*/