自定义函数查询（1，2，3，4）返回对应ID的name

/****** Object:  UserDefinedFunction [dbo].[GetUserName]    Script Date: 11/13/2013 09:27:13 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
ALTER FUNCTION [dbo].[GetUserName]
(@str nvarchar(max), --字符串
@spliter nvarchar(10)) --分割符
returns nvarchar(max)--返回构造好的Account_Name
AS 
BEGIN 
DECLARE @Result nvarchar(max)
DECLARE @UserName nvarchar(64)
DECLARE @Num int
DECLARE @Pos int
DECLARE @NextPos int
SET @Num = 0 
SET @Pos = 1 
SET @Result=''
 WHILE(@Pos <= LEN(@str)) 
 BEGIN 
  SELECT @NextPos = CHARINDEX(@spliter, @str, @Pos)
  IF (@NextPos = 0 OR @NextPos IS NULL) 
  SELECT @NextPos = LEN(@str) + 1
  SELECT @UserName=Account_Name FROM Biz_Account WHERE Account_ID=RTRIM(LTRIM(SUBSTRING(@str, @Pos, @NextPos - @Pos)))
  SET @Result = @Result + @UserName +','
  SELECT @Pos = @NextPos+1 
 END
RETURN @Result
END