クエリで解決できないエラーが発生します。
私のクエリ:
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'
「lev=3」でエラーが発生
Msg 207, Level 16, State 1, Line 2
Invalid column name 'lev'.
私のテーブルの列は次のとおりです。
    [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