Wrong query results: due to date format?

Question

hello,
I have oracle 11 and when I execute this query:
select MYDATE from mytable order by MYDATE DESC;
it get me a bad order:
MYDATE
25-MAR-09
13-MAR-09
10-MAR-10
10-MAR-10
31-JAN-10
29-JAN-10
28-JAN-10
08-DEC-09
07-DEC-09
06-DEC-09
05-DEC-09
is it may due to a wrong date format?
where have I to look out? init.ora?

Answer 1

But, there is no problem at my end (Using Oracle 10.2.0.1 on win xp):
SQL> create table t(mydate date);
Table created.
SQL> insert into t values(to_date('25-MAR-09','DD-MON-YY'));
1 row created.
SQL> insert into t values(to_date('13-MAR-09','DD-MON-YY'));
1 row created.
SQL> insert into t values(to_date('31-JAN-10','DD-MON-YY'));
1 row created.
SQL> insert into t values(to_date('07-DEC-09','DD-MON-YY'));
1 row created.
SQL> insert into t values(to_date('05-DEC-09','DD-MON-YY'));
1 row created.
SQL> insert into t values(to_date('06-DEC-09','DD-MON-YY'));
1 row created.
SQL> insert into t values(to_date('08-DEC-09','DD-MON-YY'));
1 row created.
SQL> insert into t values(to_date('10-MAR-09','DD-MON-YY'));
1 row created.
SQL> insert into t values(to_date('29-JAN-10','DD-MON-YY'));
1 row created.
SQL> insert into t values(to_date('10-MAR-10','DD-MON-YY'));
1 row created.
SQL> insert into t values(to_date('28-JAN-10','DD-MON-YY'));
1 row created.
SQL> select * from t;
MYDATE
25-MAR-09
13-MAR-09
31-JAN-10
07-DEC-09
05-DEC-09
06-DEC-09
08-DEC-09
10-MAR-09
29-JAN-10
10-MAR-10
28-JAN-10
11 rows selected.
SQL> SELECT MYDATE FROM T ORDER BY MYDATE DESC;
MYDATE
10-MAR-10
31-JAN-10
29-JAN-10
28-JAN-10
08-DEC-09
07-DEC-09
06-DEC-09
05-DEC-09
25-MAR-09
13-MAR-09
10-MAR-09
11 rows selected.
SQL> SHOW PARAMETER NLS_DATE;
NAME                                 TYPE        VALUE
nls_date_format                      string
nls_date_language                    stringCan you show us the output of
show parameter nls_date;
Regards
Girish Sharma