If you cannot grok the overall structure of a program while taking a shower, you are not ready to code it. Richard Pattis
The DUAL table is a special one-row, one-column table present by default in Oracle and other database installations. The sysdate returns the current date from the oracle database server.
SELECT sysdate from dual;
The to_char funcation format the date.
SELECT TO_CHAR(SYSDATE, 'MM-DD-YYYY HH24:MI:SS') "NOW" FROM DUAL;