Oracle PL/SQL Tutorial/SQL PLUS Session Environment/nls date format
alter session set nls_date_format="dd-mm-yyyy", nls_language=Dutch, nls_currency="Eur"
SQL> alter session
2 set nls_date_format="dd-mm-yyyy"
3 nls_language=Dutch
4 nls_currency="Eur";
Session altered.
SQL>
SQL>
alter session set nls_date_format = "SYYYYMMDD HH24MISS";
SQL>
SQL>
SQL> alter session set nls_date_format = "SYYYYMMDD HH24MISS";
Session altered.
SQL>
SQL>