SQL Server removes a character in front of a string

Because this side of the database is more, the data is more, but there is a legacy of historical data problems; A string preceded by a comma;

Now the demand is to get rid of the English comma, with a script to run the database is also OK, but here with SQL statements to remove;

Here's the complete code, here's a record.

DECLARE @cursor CURSOR;DECLARE @id    int;DECLARE @Staging    varchar(Max);DECLARE @Staging_tmp    varchar(Max);DECLARE @str_len int;DECLARE @start_num    int;Set @cursor = CURSOR  for SELECTId,staging fromProj_dong_infowhereStaging<> "'  andStaging is  not NULL;OPEN @cursor    FETCH NEXT  from @cursor  into @id,@Staging     while(@ @FETCH_STATUS=0)        BEGIN        SET @Staging_tmp = LTrim(@Staging); SET @start_num = Patindex('%,%',@Staging_tmp); IF @start_num = 1            BEGIN                SET @start_num = Patindex('%,%',@Staging); SET @str_len = datalength(@Staging); SET @Staging = substring(@Staging,@start_num+1,@str_len); --PRINT @Staging;                --PRINT @id;                UpdateProj_dong_infoSetStaging= @Staging whereId= @id; END            FETCH NEXT  from @cursor  into @id,@Staging        END    CLOSE @cursor    deallocate @cursor

SQL Server removes a character in front of a string