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*/