Instead of:
FROM formation f, ref_unite_de_duree u, ref_unite_de_duree u1
LEFT OUTER JOIN ON (f.unite_duree_entreprise=u.id
AND f.unite_duree_totale=u1.id)
try:
FROM formation f LEFT OUTER JOIN ref_unite_de_duree u ON
(f.unite_duree_entreprise=u.id)
LEFT OUTER JOIN ref_unite_de_duree u1 ON
(f.unite_duree_entreprise=u1.id)
I don't know if the results are that you expect but the sintax, I think
is correct !
Best regards, Luis Sousa