SQL Distinct Count 和 Case when

Question

這是我對 Microsoft SQL Server 的查詢：

select count(distinct AEN) as Customers  
from 
(   select top 100 ERDAT, AEN,  
    case 
        when AEN = 'MBLE' AND ERDAT between '20220401' and '20220430' then 'Mobile'
        when AEN = 'ISU' AND ERDAT between '20220401' and '20220430' then 'Website'
        when AEN = 'CRM' AND ERDAT between '20220401' and '20220430' then 'CRM'
        when AEN like '_[0-9]%' AND ERDAT between '20220401' and '20220430' then 'ID Number'
        else 'Others'
    end as 'Channels' 
    from [Table]
)

顯然括號有問題。 任何幫助深表感謝！ :)

Answer 1

正如評論中已經提到的，您的子查詢需要一個別名。

改變這個

count(distinct AEN) as Customers  

進入這個

count(distinct t.AEN) as Customers  

還有這個

    [table]
)

進入這個

    [table]
) t

看看這個DBFiddle

這將在沒有錯誤的情況下運行，但我不知道這是否是您想要實現的目標，您的問題對此並不清楚