bcm@bcm-laptop:~$ oerr ora 1417
01417, 00000, "a table may be outer joined to at most one other table"
// *Cause:  a.b (+) = b.b and a.c (+) = c.c is not allowed
// *Action: Check that this is really what you want, then join b and c first
//          in a view.

select  D.Numero,
        B.date,
        B.commentaire,
        D.Libelle
  from  (
         select  A.Numero,
                 A.DemNumero,
                 C.Libelle
           from  A,
                 C
           where A.codeLibelle = C.codeLibelle
        ) D,
        B
  where CONCAT(D.Numero,CONCAT(D.DemNumero,D.Libelle)) = B.Type(+)
/

select  A.Numero,
        B.date,
        B.commentaire,
        C.Libelle
  from      A
        join
            C
          on A.codeLibelle = C.codeLibelle
        left join
            B
          on CONCAT(A.Numero,CONCAT(A.DemNumero,C.Libelle)) = B.Type
/

SQL> select  A.Numero,
  2          B.dt,
  3          B.commentaire,
  4          C.Libelle
  5    from      A
  6          join
  7              C
  8            on A.codeLibelle = C.codeLibelle
  9          left join
 10              B
 11            on CONCAT(A.Numero,CONCAT(A.DemNumero,C.Libelle)) = B.Type
 12  /

no rows selected

SQL>