SQL存储过程：批量替换数据库表列关键字

Create proc dbo.UpdateTextColumn
@Table varchar(100),
@Columns varchar(200),
@old varchar(100),
@new varchar(100)
as
    set nocount on
    declare @sql nvarchar(2000)
    declare @Column varchar(50)
    declare @cpos int,@npos int
    set @cpos=1;
    set @npos=1;
    set @npos=charindex(',',@Columns,@cpos);

    while(@npos>0)
    begin
        set @Column = substring(@Columns,@cpos,@npos-@cpos);
        set @cpos = @npos+1
        set @npos=charindex(',',@Columns,@cpos);
        
        set @sql = 'update '+@Table+' set '+@Column+'=replace(cast('+@Column+' as varchar(8000)),@old,@new) where Datalength('+@Column+')<=8000';
        EXECUTE sp_executesql @Sql,
                           N'@old varchar(100),@new varchar(100)',
                           @old,
                           @new
        declare @ptr binary(16) ,@offset int,@dellen int
        
        set @dellen = len(@old)
        
        set @offset = 1