The TO_DAYS function returns the number of days after year 0 in the rage of 366 to 3652424 from specified argument. You can specify DATE type; the value is returned in INTEGER type.
It is not recommended to use the TO_DAYS function for dates prior to the year 1582, as the function does not take dates prior to the introduction of the Gregorian Calendar into account.
TO_DAYS(date)
SELECT TO_DAYS('2010-10-04');
to_days('2010-10-04')
========================
734414
SELECT TO_DAYS('2010-10-04 12:34:56');
to_days('2010-10-04 12:34:56')
================================
734414
SELECT TO_DAYS('2010-10-04 12:34:56.7890');
to_days('2010-10-04 12:34:56.7890')
======================================
734414
SELECT TO_DAYS('1-1-1');
to_days('1-1-1')
===================
366
SELECT TO_DAYS('9999-12-31');
to_days('9999-12-31')
========================
3652424
SELECT TO_DAYS ('12:34:56');
ERROR: Conversion error in date format.