where中使用变量的问题
我想在视图中使用变量,下面的写法不对请教应如何写?

declare @yf varchar(20)
--set @yf=201203
SELECT a.月份, a.退货后回款 AS hk, a.本年回款, a.zyid, a.编码
FROM dbo.gzlj a INNER JOIN
  (SELECT zyid, MAX(月份) 月份
  FROM gzlj
  WHERE 月份 < @yf GROUP BY zyid) b ON a.zyid = b.zyid AND a.月份 = b.月份
WHERE (a.本年回款 > 0)

------解决方案--------------------
CREATE FUNCTION F_VIEW(@yf varchar(20)) 
RETURNS TABLE 
AS 
RETURN (SELECT a.月份, a.退货后回款 AS hk, a.本年回款, a.zyid, a.编码
FROM dbo.gzlj a INNER JOIN
(SELECT zyid, MAX(月份) 月份
FROM gzlj
WHERE 月份 < @yf GROUP BY zyid) b ON a.zyid = b.zyid AND a.月份 = b.月份
WHERE (a.本年回款 > 0)) 
GO 

SELECT * FROM DBO.F_VIEW('201203')