I collected many topics to make universal function with many outputs (years, months, days, hours, minutes, seconds) with string or parse to int and direction +- if you need to know what side is direction of the difference.
Use example:
$date1='2016-05-27 02:00:00';
$format='Y-m-d H:i:s';
echo timeDifference($date1, $format, '2017-08-30 00:01:59', $format);
#1 years 3 months 2 days 22 hours 1 minutes 59 seconds (string)
echo timeDifference($date1, $format, '2017-08-30 00:01:59', $format,false, '%a days %h hours');
#459 days 22 hours (string)
echo timeDifference('2016-05-27 00:00:00', $format, '2017-08-30 00:01:59', $format,true, '%d days -> %H:%I:%S', true);
#-3 days -> 00:01:59 (string)
echo timeDifference($date1, $format, '2016-05-27 00:05:51', $format, false, 'seconds');
#9 (string)
echo timeDifference($date1, $format, '2016-05-27 07:00:00', $format, false, 'hours');
#5 (string)
echo timeDifference($date1, $format, '2016-05-27 07:00:00', $format, true, 'hours');
#-5 (string)
echo timeDifference($date1, $format, '2016-05-27 07:00:00', $format, true, 'hours',true);
#-5 (int)
Function
function timeDifference($date1_pm_checked, $date1_format,$date2, $date2_format, $plus_minus=false, $return='all', $parseInt=false)
{
$strtotime1=strtotime($date1_pm_checked);
$strtotime2=strtotime($date2);
$date1 = new DateTime(date($date1_format, $strtotime1));
$date2 = new DateTime(date($date2_format, $strtotime2));
$interval=$date1->diff($date2);
$plus_minus=(empty($plus_minus)) ? '' : ( ($strtotime1 > $strtotime2) ? '+' : '-'); # +/-/no_sign before value
switch($return)
{
case 'y';
case 'year';
case 'years';
$elapsed = $interval->format($plus_minus.'%y');
break;
case 'm';
case 'month';
case 'months';
$elapsed = $interval->format($plus_minus.'%m');
break;
case 'a';
case 'day';
case 'days';
$elapsed = $interval->format($plus_minus.'%a');
break;
case 'd';
$elapsed = $interval->format($plus_minus.'%d');
break;
case 'h';
case 'hour';
case 'hours';
$elapsed = $interval->format($plus_minus.'%h');
break;
case 'i';
case 'minute';
case 'minutes';
$elapsed = $interval->format($plus_minus.'%i');
break;
case 's';
case 'second';
case 'seconds';
$elapsed = $interval->format($plus_minus.'%s');
break;
case 'all':
$parseInt=false;
$elapsed = $plus_minus.$interval->format('%y years %m months %d days %h hours %i minutes %s seconds');
break;
default:
$parseInt=false;
$elapsed = $plus_minus.$interval->format($return);
}
if($parseInt)
return (int) $elapsed;
else
return $elapsed;
}