TO_DATE('29-DEC-1988','dd-mon-yyyy') : Date Functions « PL SQL Data Types « Oracle PL/SQL Tutorial

SQL>
SQL> DECLARE
  2     start_date DATE;
  3     end_date DATE;
  4     service_interval INTERVAL YEAR TO MONTH;
  5     years_of_service NUMBER;
  6     months_of_service NUMBER;
  7  BEGIN
  8
  9     start_date := TO_DATE('29-DEC-1988','dd-mon-yyyy');
 10     end_date := TO_DATE ('26-DEC-1995','dd-mon-yyyy');
 11
 12  END;
 13  /

PL/SQL procedure successfully completed.

SQL>

21.10.Date Functions
	21.10.1.	Working with dates and built-in functions EXTRACT
	21.10.2.	TRUNC and ROUND
	21.10.3.	ROUND
	21.10.4.	ADD_MONTHS
	21.10.5.	LAST_DAY
	21.10.6.	MONTHS_BETWEEN
	21.10.7.	Use TRUNC to get only the time
	21.10.8.	Returning a point just before a specific midnight with TRUNC
	21.10.9.	TO_DATE('29-DEC-1988','dd-mon-yyyy')