SQL Server 多条记录的某个字段拼接

USE [FM_Dev]
GO
/****** 对象:  UserDefinedFunction [dbo].[GetClassNameByStudentCode]    脚本日期: 05/23/2014 17:20:43 ******/
SET ANSI_NULLS ON
SET QUOTED_IDENTIFIER GO

-- =============================================
-- Author:  Create date: 2014年5月7日 Description: 根据学员编号获取学员报读的班级名称拼接字符串 =============================================
CREATE FUNCTION dbo].GetClassNameByStudentCode] 
(
    @StudentCode varchar(50)
)
RETURNS 100)
AS
BEGIN

    declare @ClassName nvarchar(200)
    set @ClassName=''

    select @ClassName = + ClassName + ',' 
    from FM_Class cls
    join FM_StudentClass sc on sc.ClassCode=cls.ClassCode 
    where sc.code=@StudentCode
    order by cls.Id

    if <>'' 
    begin
        = left(@ClassName,len(@ClassName)-1end

    return @ClassName

END