select champ1, champ2 from table order by champ1 desc, id desc limit 10; --> plus de 10 enregistrements sont affichés, les enregistrements à valeur nulle ne sont pas affichés.
select champ1, champ2 from table order by id desc limit 10, champ1 desc; --> Erreur : You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'champ1 DESC' at line 1