sql server 中标量值函数根据id返回结果

USE [OA_WEB_DB]
GO
/****** Object:  UserDefinedFunction [dbo].[CountResult]    Script Date: 05/20/2013 16:05:04 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
ALTER function [dbo].[CountResult](@scode varchar(10))
Returns real
As
Begin
   Declare @avg real
   Declare @code varchar(11)
   Set @code=@scode
   Select @avg=COUNT(*) from OA_DT_Attach where file_id=@code and deleted=0

Return @avg
End