sql2000存储过程 截取字符串

环境如下 @Receiver="1,2,3,4,5,8,"  截取receiver
代码如下
@Receiver="1,2,3,4,5,8,"
declare @i  int

   set @i=0

    while (@i<=len(@Receiver))
    begin
       set @i=charindex(',',@Receiver)
       insert into T_Document_User (DocID,Receiver) values(@DocID,left(@Receiver,@i-1))
       set @Receiver=right(@Receiver,len(@Receiver)-@i)
    end