php diff two datetime by seconds code example
Example 1: date diff php
$datetime1 = new DateTime('2020-10-11 16:52:52');
$datetime2 = new DateTime('2020-10-13 16:52:52');
$interval = $datetime1->diff($datetime2);
echo $interval->format('%a days');
Example 2: difference of two dates in seconds php
$timeFirst = strtotime('2011-05-12 18:20:20');
$timeSecond = strtotime('2011-05-13 18:20:20');
$differenceInSeconds = $timeSecond - $timeFirst;