>i get the sum result of the first item_name two times
>and the result of the second item is not come out

No, it should work Ok, just be careful, please. Check that tmp1 and tmp2 came out Ok. Then try inner join (no UNIONs), check result again, then add first UNION, check again, then second UNION.
BTW, don't cut off previous part of the thread. It makes difficult to respond.