select t.aaa from (select a.aaa aaa,b.bbb bbb from b right join a on
a.aaa=b.bbb )t
where t.bbb is null
或
select t.aaa from (select a.aaa aaa,b.bbb bbb from a left join b on
a.aaa=b.bbb )t
where t.bbb is null
a.aaa=b.bbb )t
where t.bbb is null
或
select t.aaa from (select a.aaa aaa,b.bbb bbb from a left join b on
a.aaa=b.bbb )t
where t.bbb is null
--对不起,全部更正一下,我将你的两个表结果看反了
--第一种做法:select bbb from b where bbb not in (select aaa from a)--第二种做法:
select t.bbb from (select b.bbb bbb,a.aaa aaa from a right join b on
a.aaa=b.bbb )t
where t.aaa is null---第三种做法:select t.bbb from (select b.bbb bbb,a.aaa aaa from a left join b on
a.aaa=b.bbb )t
where t.aaa is null