一个查询的有关问题！

一个查询的问题！！！！！！！！

SQL code

/*两个表结构一样，Id    int    LoginName    varchar(50)    num    int    Grade    int    数据如下：t11    zhangsan    1    12    lisi    4    13    wangwu    7    44    xiaoming    3    3t21    zhangsan    8    12    lisi    9    13    wangwu    8    44    xiaoming    8    3怎么可以查询成下面的结果根据去除重复的loginname获取sum(num)1 zhangsan 9  12 lisi    13 13 wangwu 15 44 xiaoming 11 3*/

SQL code

select a.id,a.loginname,a.num+b.num as num a.gradefrom t1 a inner join t2 b on a.id=b.id
[解决办法]
SELECT ID,LOGINNAME,SUM(NUM),GRADE
FROM
(SELECT * FROM A
UNION ALL  
SELECT * FROM B)
T  
GROUP BY ID,LOGINNAME,GRADE

[解决办法]
SQL code
select LoginName,sum(num) from(select LoginName,num from A union all select LoginName,num from B)tgroup by LoginName
[解决办法]
SQL code
select LoginName,sum(num) from(select LoginName,num from A union all select LoginName,num from B)tgroup by LoginName