TRUNC

The Oracle and PL/SQL TRUNC function returns a date truncated to the unit specified by the format model fmt.

TRUNC(d [,fmt])

The value returned is always of datatype DATE.

If you omit fmt, then date is truncated to the nearest day.

Example 1:

SELECT TRUNC(TO_DATE('31/10/2015','DD/MM/YYYY'),'YYYY') FROM DUAL;

returns:

01/01/2015

Example 2:

SELECT TRUNC(TO_DATE('31/10/2015','DD/MM/YYYY'),'MM') FROM DUAL;

returns:

01/10/2015