Question

SQL问题,A，B两张表，都有ID这一列，如何提取两张表的这一列中不相同的值，求指导

Answer 1

这还不容易，直接写sql语句

select * from a where id not in (select id from b )

这样不是直接可以查出a表中没在b表的中id值吗。

Answer 2

select ID from A left join B on A.id=B.id where B.id is null
union all
select ID from B left join A on A.id=B.id where A.id is null

Answer 3

select * from a ,b where a.id<>b,id