求MYSQL语句，解决两表查询问题判断A表与B表同一name的num总值是否相等，取出总值不相等的记录。

A 表 结构
ID  name  num
1   小明   20
2   小明   21
3   大明   15
4   大明   13

B 表 结构
ID  name  num
1   小明   18
2   小明   19
3   大明   15
4   大明   13

SELECT * FROM a 
WHERE a.name NOT IN
(
 #查总值相等
 SELECT t1.name
 FROM (SELECT NAME, SUM(num) AS num FROM a GROUP BY NAME) t1
 JOIN 
 (SELECT NAME,SUM(num) AS num FROM b GROUP BY NAME) t2 ON t1.name=t2.name AND t1.num=t2.num
)

select distinct  * from
((select A.* from A join B on A.name = B.name where A.num <> B.num)
union
(select A.* from B join A on A.name = B.name where A.num <> B.num))