在选择语句创建的列上无效的列名称

Question

我将问题简化为以下select语句。

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，而只是一个在此select语句中获取值的列。

有没有办法做到上述没有得到 无效的列名称aVariable错误？

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必须像这样：

select 
    u.UserId, 
    1 as aVariable 
from TblUser u 

Answer 3

您选择是正确的说法是没有意义的。

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 

上面的声明表示如果有一个用户被禁用，则选择来自tbluser的所有用户。

我想你想看到表中的用户被禁用。如果是这样，那么你想要以下选择语句：

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

给这个镜头。

先前回答删除，因为问题有点不清楚。

Answer 4

你需要这样做：

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