子查询列错误

Question

出现错误，在我的询问，我解决不了：

我的查询：

SELECT [subject], cal 
FROM (
    SELECT [subject], cal 
    FROM amir 
    WHERE textfilter LIKE '% word %') a 
WHERE lev=3 AND cal between '6/10/2012' AND '3/11/2013' 

在出现的错误 “列弗= 3”

Msg 207, Level 16, State 1, Line 2 
Invalid column name 'lev'. 

我表列为：

[RecordId] [bigint] IDENTITY(1,1) NOT NULL, 
    [text] [nvarchar](max) NOT NULL, 
    [textfilter] [nvarchar](max) NOT NULL, 
    [mo] [int] NULL, 
    [loc] [int] NULL, 
    [lev] [int] NOT NULL, 
    [cal] [date] NOT NULL, 
CONSTRAINT [PK_SahifehEmam] PRIMARY KEY CLUSTERED 

Answer 1

您不选择lev在你的子查询中，所以它在主查询中不可用。

你可以把它添加到您的子查询是这样的：

select [subject], cal 
from (
    select [subject], cal, lev 
    from amir 
    where textfilter like '% word %' 
) a 
where lev=3 AND cal between '6/10/2012' AND '3/11/2013' 

虽然我甚至不明白为什么子查询是必要的：

select [subject], cal 
from amir 
where textfilter like '% word %' and lev=3 AND 
    cal between '6/10/2012' AND '3/11/2013'