在選擇語句創建的列上無效的列名稱

Question

我將問題簡化爲以下select語句。

select 
    u.UserId, 
    aVariable = cast((case when exists(select * from TblUser u where u.Disabled=1) then 1 else 0 end) as bit), 
from TblUser u 
where aVariable = 1 

aVariable不是表的列，而只是一個在此select語句中獲取值的列。

有沒有辦法做到上述沒有得到 無效的列名稱aVariable錯誤？

Answer 1

select q.* from (
select 
    u.UserId, 
    cast((case when exists(select * from TblUser u where u.Disabled=1) then 1 else 0 end) as bit) as aVar, 
from TblUser u 
)q 
where q.aVar = 1 

Answer 2

的SELECT必須像這樣：

select 
    u.UserId, 
    1 as aVariable 
from TblUser u 

Answer 3

您選擇是正確的說法是沒有意義的。

select q.* from (
select 
    u.UserId, 
    cast((case when exists(select * from TblUser u where u.Disabled=1) then 1 else 0 end) as bit) as aVar, 
from TblUser u 
)q 
where q.aVar = 1 

上面的聲明表示如果有一個用戶被禁用，則選擇來自tbluser的所有用戶。

我想你想看到表中的用戶被禁用。如果是這樣，那麼你想要以下選擇語句：

SELECT userid, disabled as aVar 
FROM TblUser 
WHERE disabled = 1 

給這個鏡頭。

先前回答刪除，因爲問題有點不清楚。

Answer 4

你需要這樣做：

select 
    u.UserId, 
    aVariable = cast((case when exists(select * from TblUser u where u.Disabled=1) then 1 else 0 end) as bit), 
from TblUser u 
where cast((case when exists(select * from TblUser u where u.Disabled=1) then 1 else 0 end) as bit) = 1