（MS SQL Server）使用公式設置案例語句列名稱

Question

我想使用公式爲案例語句設置列名，但不接受簡單的方法。下面是我試圖做的例子 - 有沒有辦法做到這一點？

select 

ID 

-- Pull DeDupe_Decision_Count for that ID last month (EOM_Date), where each ID has multiple rows in the data set for each data month 

, sum(case when EOM_Date = CONVERT(DATE, DATEADD(s,-1,DATEADD(m,-1,DATEADD(mm, DATEDIFF(m,0,GETDATE()),0)))) 
then DeDupe_Decision_Count end) 
as CONVERT(DATE, DATEADD(s,-1,DATEADD(m,-1,DATEADD(mm, DATEDIFF(m,0,GETDATE()),0)))) 

-- Pulling the same for two months ago 

, sum(case when EOM_Date = CONVERT(DATE, DATEADD(s,-1,DATEADD(m,-2,DATEADD(mm, DATEDIFF(m,0,GETDATE()),0)))) 
then DeDupe_Decision_Count end) 
as CONVERT(DATE, DATEADD(s,-2,DATEADD(m,-1,DATEADD(mm, DATEDIFF(m,0,GETDATE()),0)))) 

-- Pulling the same for three months ago 

, sum(case when EOM_Date = CONVERT(DATE, DATEADD(s,-1,DATEADD(m,-3,DATEADD(mm, DATEDIFF(m,0,GETDATE()),0)))) 
then DeDupe_Decision_Count end) 
as CONVERT(DATE, DATEADD(s,-2,DATEADD(m,-1,DATEADD(mm, DATEDIFF(m,0,GETDATE()),0)))) 

-- Would like to do the same for 12-24 months 
from Mytable 
group by ID 

我想用公式代替靜態日期，因爲這將每月更新幷包含12-24個月的數據。我可以使用變量，並在上個月，2個月前，3個月前等列出名稱，但我寧願列名稱是月份的日期。

Answer 1

這需要動態查詢

DECLARE @sql VARCHAR(max) 

SET @sql = 'select 
case 

when EOM_Date = CONVERT(DATE, DATEADD(s,-1,DATEADD(mm, DATEDIFF(m,0,GETDATE()),0))) 

then ''DeDupe_Decision_Count'' 

end as '+ Quotename(CONVERT(DATE, Dateadd(s, -1, Dateadd(mm, Datediff(m, 0, Getdate()), 0)))) 

PRINT @sql 

exec(@sql)