Returns a date truncated so as to remove specified smaller units.
Truncate the current time, setting hours to 0 (12am).
dateTrunc(date expr d, string part)
Returns to the rounded value of a timestamp to the interval needed according to part. Suppose $currenttime_ evaluates to 8/25/19 11:28:44 AM. Then,
dateTrunc($currentTime, 'day') would return 8/25/19 12:00:00 AM.
Allowed values for part are: