SQL & PL/SQL

Hello,

I ran NLS_DATE_FORMAT to modify date but it is not getting changed. Can you please advise the reason for same?

I am using Oracle 10.2 SQL Plus client and have run following commands on PL/SQL Developer Command Window.

SQL> ALTER SESSION SET NLS_DATE_FORMAT = 'YYYY MM DD';

Session altered
SQL> select sysdate from dual;

SYSDATE
-----------
4/22/2013 1

Thanks in advance,
Tinku