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：

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*/