-- 3.这样应该会高点:Select
ClassId,
Max(Info1),
Max(Info2),[...]
Sum(GoodsNum) as TotalNum
From
T_A ,T_B where T_A.ClassId=T_B.ClassId
Group by T_A.ClassId
ClassId,
Max(Info1),
Max(Info2),[...]
Sum(GoodsNum) as TotalNum
From
T_A ,T_B where T_A.ClassId=T_B.ClassId
Group by T_A.ClassId
select T_A.*,sum(GoodsNum)as TotalNum
from T_A,T_B where T_A.ClassId=T_B.ClassId
这样就可以不用group by 了,可以做到更有效,如果说你的T_A表classid不是唯一的那可以采用
lsp69(浪子神剑) 的查询语句