请高手分析下这个SQL语句，关于group by 和 sum的

create view TEMP as Select src as src, dst as dst, sum(gtp_bytes) as gtp_bytes From t1 where ( ( dst = -2067090979 )) group by src,dst 
union Select src as src, dst as dst, sum(gtp_bytes) as gtp_bytes From t1 where ( ( dst = -2067090979 )) group by src,dst  
union Select src as src, dst as dst, sum(gtp_bytes) as gtp_bytes From t1 where ( ( dst = -2067090979 )) group by src,dst  

执行这个SQL语句建立了一个视图
然后分别执行
select gtp_bytes as gtp_bytes from TEMP group by src,dst
select sum(gtp_bytes) as gtp_bytes from TEMP group by src,dst
这两个语句得到的查询结果不同，这是为什么
按我的理解在创建视图的时候已经做了sum的汇聚

select gtp_bytes as gtp_bytes from TEMP group by src,dst
不是标准的SQL语句

那应该怎么写

union 改成union all试试. ^^