pg_fieldisnull analogon in mysql?

Hi folks Is there a way to check a field out of an existing db result if it is NULL in mysql? According to the manuals this must be one of the differences between postgresql and mysql. Does anybody know a work-around to get it? Notice: I have a normal, existing query result that doesn't check for NULL values - something like int mysql_fieldisnull (int result_id, int row, mixed field) (adapted from the pg function ;-)) Or do I have to resend another query that does NULL checking explicitly? Thank for advice Regards Steff