表A:
PID PNAME
表B:
PID PNAME怎么从A表中找出B表中A.PID<>B.PID的数据呢?
我这么写不对会有很多重复数据!
SELECT A.PNAME,A.PID FROM AAA A,BBB B WHERE B.PID NOT IN P.AID;
PID PNAME
表B:
PID PNAME怎么从A表中找出B表中A.PID<>B.PID的数据呢?
我这么写不对会有很多重复数据!
SELECT A.PNAME,A.PID FROM AAA A,BBB B WHERE B.PID NOT IN P.AID;
not exists
(select 1 from b where a.pid = b.pid);