Question

查询1返回一个数字 AveSpace，即100

select avg(spaceusage) as AveSpace
from
(
select top (5) *  from Employee
order by Date desc
) as s

查询2返回一个数字 TotalSpace，即1000

select top(1) TotalSpace from SpaceTable
order by date

我想将结果合并到一个数据集中，并添加第三列unitSpace，用于计算查询2 /查询1的结果，即1000/100 = 10

输出3列

[AveSpace] [TotalSpace] [unitSpace]

100          1000          10

Answer 1

将每个单独的查询视为子查询，然后计算结果：

SELECT a.AveSpace, b.TotalSpace, (CAST(a.AveSpace AS float) / CAST(b.TotalSpace AS float)) as UnitSpace
FROM 
    (
        SELECT TOP 1 AVG(spaceusage) as AveSpace FROM (SELECT TOP 5 * FROM Employee ORDER BY date DESC)
    ) a,
    (
         SELECT TOP 1 TotalSpace FROM SpaceTable ORDER BY date
    ) b

Answer 2

宣布@TotalSpace FLOAT

SELECT TOP 1 @TotalSpace = SpaceTable的TotalSpace 按日期排序

SELECT选择avg（spaceusage）为AveSpace，@ TotalSpace AS TotalSpace，@ TotalSpace / avg（spaceusage）AS unitSpace 从（从员工中选择top（5）* 按日期排序）作为s

将两个查询结果合并为一个并使用结果计算另一列

2 个答案: