SQL

oracle set date format

ALTER SESSION SET NLS_DATE_FORMAT = 'DD-MM-YYYY HH24:MI:SS';
SELECT sysdate FROM dual;

SELECT to_char(sysdate,'HH24:MI:SS') FROM dual;

oracle default date format

SELECT
  TO_DATE( '24-JUL-21', 'DD-MON-RR' )
FROM
  dual;