SQL Distinct Count 和 Case when

Question

这是我对 Microsoft SQL Server 的查询：

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]
)

显然括号有问题。 任何帮助深表感谢！ :)

Answer 1

正如评论中已经提到的，您的子查询需要一个别名。

改变这个

count(distinct AEN) as Customers  

进入这个

count(distinct t.AEN) as Customers  

还有这个

    [table]
)

进入这个

    [table]
) t

看看这个DBFiddle

这将在没有错误的情况下运行，但我不知道这是否是您想要实现的目标，您的问题对此并不清楚