Oracle集合运算
--并集运算 UNION ALL 不去掉重复记录
select * from t_owners where id < 7
union all
select * from t_owners where id < 5
--并集运算 UNION 去掉重复记录
select * from t_owners where id < 7
union
select * from t_owners where id < 5
--交集运算
select * from t_owners where id < 7
intersect
select * from t_owners where id < 5
--差集运算
select * from t_owners where id < 7
minus
select * from t_owners where id <5