今天存储过程被卡

CREATE PROCEDURE sp_UpdateBulletinByWorkId
                      @WorkId varchar(6),
                      @Id int,
                      @retFlag int out
 AS

Declare @PointerPrev int
Declare @PointerCurr int
Declare @WorkReader varchar(100)
Declare @temp varchar(10)
Set @PointerPrev=1
Set @PointerCurr=1

BEGIN TRANSACTION
Set NoCount ON

if  exists (select @WorkReader=WorkIdReader  from Bulletin where Id=@Id)
    begin
        
                         
        Set @PointerCurr=CharIndex(',',@WorkReader,@PointerPrev+1)
        set @temp=cast(SUBSTRING(@WorkReader,@PointerPrev,@PointerCurr-@PointerPrev) as varchar)
                    if @temp=@WorkId
                    begin  
                    set @retFlag=0
                     return
                    end
                

        SET @PointerPrev = @PointerCurr

        while (@PointerPrev+1 < LEN(@WorkReader))
                    Begin
                    Set @PointerCurr=CharIndex(',',@WorkReader,@PointerPrev+1)
                    if(@PointerCurr>0)
                    Begin
                    set @temp=cast(SUBSTRING(@WorkReader,@PointerPrev+1,@PointerCurr-@PointerPrev-1) as varchar)

                    if @temp=@WorkId
                    begin  
                    set @retFlag=0
                     return
                    end

                    End
                        end
                    set @temp=cast(SUBSTRING(@WorkReader,@PointerPrev+1,LEN(@WorkReader)-@PointerPrev) as varchar)

                    if @temp=@WorkId
                    begin
                    set @retFlag=0
                    return
                    end

                    
                    
    end


 update Bulletin set WorkIdReader=WorkIdReader+','+@WorkId
 select  *   from Bulletin where Id=@Id

Set NoCount OFF
    begin
    set @retFlag=1
    return
    end

IF @@error = 0
BEGIN
    COMMIT TRANSACTION
           
END

ELSE
BEGIN
    ROLLBACK TRANSACTION
          
END
GO

 17行出错，问题没有解决