Mysql in PHP - how to update only one row in table but with greatest id number

Question

I am trying to update fields in my DB, but got stuck with such a simple problem: I want to update just one row in the table with the biggest id number. I would do something like

Answer 1

I have to update a table with consecutive numbers.

This is how i do.

---

UPDATE pos_facturaciondian fdu 
            SET fdu.idfacturacompra = '".$resultado["afectados"]."', 
            fdu.fechacreacion = '".$fechacreacion."'
            WHERE idfacturaciondian = 
            (
                SELECT min(idfacturaciondian) FROM 
                (   
                    SELECT * 
                    FROM pos_facturaciondian fds
                    WHERE fds.idfacturacompra = ''
                    ORDER BY fds.idfacturaciondian
                ) as idfacturaciondian
            )