Conflit entre "distinct" et "order by"

Bonjour tout le mode.
je travaille avec MySql et j'ai la table suivante
________________
| Pointage                 |
|---------------------|
|idPointage               |
|idUtilisateur             |
|idOperation             |
|idMachine               |
|idPiece                    |
|dateDebut               |
|dateFin                   |
|_______________|

je voudrai avoir une requete sql qui m'affiche (idUtilisateur,idOperation,idMachine,idPiece)sans redendance et trié selon la date debut(descendant)

j'ai essayé la requete suivante
select idPointage,idUtilisateur,idOperation,idMachine,idPiece
from utilisateur
where dateFin is not null
order by dateFin desc

mais le resultat n'est pas ordonné suivant DateFin

merci d'avance.

Avec le DateFin Desc tu ordonnes de la date la plus récente à la date la plus ancienne!!

Salut j'ai essayé ca,
et voici ce que ca me donne:
avec la requete :
SELECT *
FROM `ascii`.`pointage`
where CodeUtilisateur='0'
order by DateFin desc
j'ai mis le CodeUtilisateur égal a zero pour diminuer l'affichage et voici ce que j'obtien:

idPointage,"CodeMachine","CodeOf","CodeOp","Codeutilisateur","DateDebut","DateFin"

34,"3","1","5","0","2008-09-15 14:45:04","2008-09-15 15:53:42"

29,"1","1","1","0","2008-09-15 13:32:35","2008-09-15 15:03:16"

28,"4","2","3","0","2008-09-15 12:44:49","2008-09-15 12:47:59"

27,"1","1","5","0","2008-09-15 12:44:07","2008-09-15 12:47:50"

26,"1","1","2","0","2008-09-15 12:43:32","2008-09-15 12:47:41"

25,"2","1","1","0","2008-09-15 10:34:54","2008-09-15 12:47:31"

24,"1","1","1","0","2008-09-15 10:34:24","2008-09-15 12:47:19"

18,"1","1","1","0","2008-09-12 14:05:16","2008-09-15 10:18:33"

19,"4","2","3","0","2008-09-12 14:06:43","2008-09-15 10:18:25"

21,"1","1","2","0","2008-09-12 14:18:56","2008-09-15 10:18:16"

23,"1","2","3","0","2008-09-15 10:15:33","2008-09-15 10:17:29"

22,"1","1","5","0","2008-09-15 10:14:29","2008-09-15 10:15:03"

17,"1","1","1","0","2008-09-12 14:03:02","2008-09-12 14:21:41"

15,"2","2","3","0","2008-09-12 10:43:41","2008-09-12 14:21:24"

14,"3","1","5","0","2008-09-11 12:17:53","2008-09-12 14:21:15"

13,"1","1","1","0","2008-09-11 12:17:46","2008-09-12 14:20:46"

12,"2","2","3","0","2008-09-11 12:17:40","2008-09-12 14:20:30"

16,"4","2","6","0","2008-09-12 13:59:02","2008-09-12 14:19:17"

20,"1","1","5","0","2008-09-12 14:08:39","2008-09-12 14:09:01"

11,"3","1","5","0","2008-09-11 12:17:16","2008-09-12 14:07:22"

9,"4","2","5","0","2008-09-11 12:10:14","2008-09-11 12:13:44"

10,"2","2","3","0","2008-09-11 12:12:07","2008-09-11 12:12:32"

7,"1","1","1","0","2008-09-11 08:45:28","2008-09-11 12:07:14"

8,"4","2","5","0","2008-09-11 08:45:38","2008-09-11 08:45:49"

4,"4","1","1","0","2008-09-10 14:52:44","2008-09-11 08:45:19"

6,"1","2","3","0","2008-09-10 15:03:34","2008-09-10 15:03:51"

3,"4","2","5","0","2008-09-10 14:50:51","2008-09-10 14:51:02"

2,"1","2","3","0","2008-09-10 14:49:37","2008-09-10 14:49:52"

1,"1","2","3","0","2008-09-10 14:48:50","2008-09-10 14:49:06" moi je voudrai obtenir "CodeMachine","CodeOf","CodeOp" "3","1","5"

"1","1","1"
"4","2","3"
"1","1","5"
"1","1","2"
"2","1","1"
"1","2","3"
"2","2","3"
.......
pour cela j'ai essayé la requete suivante :
SELECT distinct CodeMachine,CodeOf,CodeOp 
FROM `ascii`.`pointage`
where CodeUtilisateur='0'
order by DateFin desc
Mais j'obtien le resultat suivant :

CodeMachine,"CodeOf","CodeOp"

2,"1","1"

4,"2","3"

1,"1","2"

4,"2","6"

1,"1","5"

3,"1","5"

2,"2","3"

1,"1","1"

4,"1","1"

4,"2","5"

1,"2","3"

3,"1","1"

ce qui ne colle pas logiquement avec la requete