从选择结果中选择具有最大值的行

【问题标题】：Select rows with maximum value from select result从选择结果中选择具有最大值的行
【发布时间】：2017-11-08 08:22:23
【问题描述】：

我想从以下选择中选择具有最大值的行，但是子查询中的结果表名称错误（select max(result.Sum) from result）：

select *
from 
(select sum(Rooms.n_seats) as 'Sum', DepKinds.title
from Rooms join Departments on Rooms.department = Departments.id
join DepKinds on Departments.kind = DepKinds.id group by DepKinds.title) result where result.Sum = (select max(result.Sum) from result);

那么如何为这些总和选择最大总和和标题？

【问题讨论】：

标签： sql select

【解决方案1】：

不能在子查询中使用FROM 后面的result 别名。尝试使用HAVING。

select sum(Rooms.n_seats) as 'Sum', DepKinds.title
from Rooms 
join Departments on Rooms.department = Departments.id
join DepKinds on Departments.kind = DepKinds.id 
group by DepKinds.title
having sum(Rooms.n_seats) >= all
(
   select sum(Rooms.n_seats) 
   from Rooms 
   join Departments on Rooms.department = Departments.id
   join DepKinds on Departments.kind = DepKinds.id 
   group by DepKinds.title   
)

这将返回 all DepKinds.title 具有最大席位数。

【讨论】：