A  |---------|
DATEDEB   DATEEND

B       |-------------------|
     DATEDEB             DATEEND

Hello all,

I think the answer is more important than the format 
(to a certain point ,I agree).
The problem is that the formatting is lost,
and we spend time to translate into English.
(Yes we can!)
I put two tags (code and /code)!

Thank you anyway for your answers.

Hello,
I think my problem solved this way:

SQL> ed
écrit file afiedt.buf

  1  SELECT *
  2  FROM   CONTRAT A, CONTRAT B
  3  WHERE  (A.DATEDEB,A.DATEEND) OVERLAPS (B.DATEDEB,B.DATEEND)
  4* and a.datedeb<>b.datedeb and a.dateend<>b.dateend
SQL> r
  1  SELECT *
  2  FROM   CONTRAT A, CONTRAT B
  3  WHERE  (A.DATEDEB,A.DATEEND) OVERLAPS (B.DATEDEB,B.DATEEND)
  4* and a.datedeb<>b.datedeb and a.dateend<>b.dateend

    NUMSAL NUMCONTRAT DATEDEB  DATEEND      NUMSAL NUMCONTRAT DATEDEB  DATEEND
---------- ---------- -------- -------- ---------- ---------- -------- --------
         1          1 02/02/08 10/03/08          1          3 10/02/08 15/04/08
         1          2 20/03/08 30/04/08          1          3 10/02/08 15/04/08
         1          2 20/03/08 30/04/08          1          4 16/04/08 15/05/08
         1          3 10/02/08 15/04/08          1          1 02/02/08 10/03/08
         1          3 10/02/08 15/04/08          1          2 20/03/08 30/04/08
         1          4 16/04/08 15/05/08          1          2 20/03/08 30/04/08

6 ligne(s) sélectionnée(s).

Script sql for test:
--------------------
create table contrat
(numsal number(4),
 numcontrat number(5),
 datedeb date,
 dateend date
);

insert into contrat values (1,1,'02/02/2008','10/03/2008');
insert into contrat values (1,2,'20/03/2008','30/04/2008');
insert into contrat values (1,3,'10/02/2008','15/04/2008');
insert into contrat values (1,4,'16/04/2008','15/05/2008');
insert into contrat values (1,5,'16/05/2008','31/08/2008');
insert into contrat values (1,6,'01/10/2008','31/10/2008');
insert into contrat values (1,7,'10/11/2008','31/12/2008');
insert into contrat values (1,8,'10/11/2008','15/12/2008');
commit;

FOO SCOTT>create table contrat
  2  (numsal number(4),
  3  numcontrat number(5),
  4  datedeb date,
  5  dateend date
  6  )
  7  /

Table created.

FOO SCOTT>insert into contrat values (1,2,'20/03/2008','30/04/2008');
insert into contrat values (1,2,'20/03/2008','30/04/2008')
                                *
ERROR at line 1:
ORA-01843: not a valid month