SQLServer 表查询中的 合并查询 合集 差集 交集

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
/* 求表合集
1
2
3
4
5*/
select * from t1 union all   select * from t2
go
/*求表合集不过滤重复
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*/
本文来自CSDN博客：http://blog.csdn.net/jinjazz/archive/2009/09/07/4527863.aspx