Truncates May 25, 2005, to the first day in the month

    
SQL>
SQL> SELECT TRUNC(TO_DATE('25-MAY-2005'), 'MM') FROM dual;

TRUNC(TO_
---------
01-MAY-05

SQL>

1.	formats used with the TRUNC() function for the DATE data type
2.	Trunc a date
3.	Truncates 7:45:26 P.M. on May 25, 2005, to the hour
4.	TRUNC(SYSDATE,'Q'): Truncating to the quarter
5.	TRUNC: Removing the time from SYSDATE
6.	Use TRUNC(Date value) in where clause
7.	truncate and round a date that falls into the second part of a year, the results would be different:
8.	Use TRUNC(date_variable) when you want to extract a date from a timestamp
9.	TRUNC(): truncate May 25, 2005, to the first day in the year

Truncates May 25, 2005, to the first day in the month : TRUNC Date « Date Timezone « Oracle PL / SQL