sql where 子句仅包含 if case when

Question

我想知道是否可以为多个客户端运行一个脚本，当我为指定的客户端运行时，我可以添加额外的 where 子句，而不必多次重写基本脚本？

例如。基本脚本是

SELECT Status, count(distinct T1.AccountNo)
FROM Orders (nolock), Accounts (NOLOCK)
WHERE Orders.AccountNo = Accounts .AccountNo  
AND date between '1 Oct 2011' and '31 Oct 2011'
GROUP BY Status

但是当我竞选客户 A 时，我想包括额外的标准

AND Accounts.Role IN ('User','Admin')
AND Accounts.Active= 'Y'

Answer 1

SELECT Status, count(distinct T1.AccountNo)
FROM Orders (nolock), Accounts (NOLOCK)
WHERE Orders.AccountNo = Accounts .AccountNo  
AND date between '1 Oct 2011' and '31 Oct 2011'
AND CASE WHEN Client = 'A' THEN Accounts.Role ELSE 'User' END IN ('User', 'Admin')
AND CASE WHEN Client = 'A' THEN Accounts.Active ELSE 'Y' END = 'Y'
GROUP BY Status