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：
相关测试实例如下：
代码如下: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*/