select Top n * from 中的n必须是常量么？

[coldice]

CREATE PROCEDURE [dbo].[TopRecord]
@pagesize int = 20
AS


select top @pagesize * from fileData

提示总说@pagesize附近有语法错误，如果改成常量比如top 20

则无错误。。

怎么解决？现在我必须的需要将返回得记录数由参数来控制得

[zarge]

CREATE PROCEDURE [dbo].[TopRecord]
@pagesize int = 20
AS

DECLARE @sql varchar(8000)
SET @sql = 'select top ' + CAST(@pagesize AS varchar) + '* from fileData'
EXEC(@sql)

[dotAge]

SET ROWCOUNT @pagesize
select * from fileData
SET ROWCOUNT 0