Oracle中的集合运算

差集 minus（参考链接：https://blog.csdn.net/greenappple/article/details/7073349/）

A=｛111，222，333｝ B=｛112，223，333｝,那么A\B=｛111，222｝

select * from (select 111 as a from dual
union all select 222 as a from dual
union all select 333 as a from dual)
minus
select * from (select 112 as a from dual
union all select 223 as a from dual
union all select 333 as a from dual)

执行结果为：