Question

我从过去的3、6和10个月中获得不同月份的平均值。

select SUM(GrossAmount)/10 as Averageten  
FROM Table
WHERE CreatedDate >= DATEADD(MONTH, -10, GETDATE()) 

select SUM(GrossAmount)/6 as Averagesix  
FROM Table
WHERE CreatedDate >= DATEADD(MONTH, -6, GETDATE()) 

select SUM(GrossAmount)/3 as Averagethree  
FROM Table
WHERE CreatedDate >= DATEADD(MONTH, -3, GETDATE())

例如，我得到三个不同的值：

1200.22
2300.22
4500

我想获得这三个值的平均值

(1200.22 + 2300.22 + 4500) / 3

如何从这些单独的查询中添加值。

Answer 1

使用并集合并三个查询，然后取平均值

select avg(Averageten)
from
(select SUM(GrossAmount)/10 as Averageten  
FROM Table
WHERE CreatedDate >= DATEADD(MONTH, -10, GETDATE()) 
union
select SUM(GrossAmount)/6 
FROM Table
WHERE CreatedDate >= DATEADD(MONTH, -6, GETDATE()) 
union 
select SUM(GrossAmount)/3   
FROM Table
WHERE CreatedDate >= DATEADD(MONTH, -3, GETDATE())
)a

或者，您可以使用条件聚合来查找值，因为您是从具有不同条件的同一张表中查询的

select ((sum(case when CreatedDate >= DATEADD(MONTH, -10, GETDATE()) then GrossAmount end)/10)
+(sum(case when CreatedDate >= DATEADD(MONTH, -6, GETDATE()) then GrossAmount end)/6)
+(sum(case when CreatedDate >= DATEADD(MONTH, -3, GETDATE()) then GrossAmount end)/3))/3 
from tablename

Answer 2

使用条件聚合。

SELECT
(
    SUM(CASE WHEN CreatedDate >= DATEADD(MONTH, -10, GETDATE()) THEN GrossAmount END) / 10 +
    SUM(CASE WHEN CreatedDate >= DATEADD(MONTH,  -6, GETDATE()) THEN GrossAmount END) /  6 +
    SUM(CASE WHEN CreatedDate >= DATEADD(MONTH,  -3, GETDATE()) THEN GrossAmount END) /  3
) / 3 AS [10, 6, 3 Average]
FROM Table
WHERE CreatedDate >= DATEADD(MONTH, -10, GETDATE()) -- this covers all three cases

将来自三个不同查询的数字加在一起

2 个答案: