如何使用select语句和运算符从表中导出复杂数据

Question

我有一个家庭作业问题，要求我“找出在PC上安装的软件总成本最高的PC”。

我已经可以使用以下语句找到最大的软件总成本

select max(Totalcost)'MaxTotal' from
(select tagnum, sum(softcost)'Totalcost' from software
group by tagnum) as Table1

但是，当我尝试选择与此max（Totalcost）相关的PC主键时，我一直遇到语法错误。如何选择与此最大值关联的PC主键？

任何帮助将不胜感激。我在下面的数据上附加了一个链接

Answer 1

如果有人好奇，我相信我使用以下方法找到了答案：

select comp from PC where tagnum in
(select tagnum from 
(select tagnum, sum(softcost)'Totalcost' from software
group by tagnum) as Table1
where Totalcost = 
(select max(Totalcost)'MaxTotal' 
from
(select tagnum, sum(softcost)'Totalcost' 
from software
group by tagnum
) as Table1
))