show the difference between two dates in years, months, days, hours and seconds

PHP

// this will show the difference between 2 dates, in years, days, hours, etc.
  // date format - 2016-06-01 22:45:00
  function show_date_diff($date1,$date2) {

    $date1 = strtotime($date1);
    $date2 = strtotime($date2);

    $diff = abs($date2 - $date1);

    $years = floor($diff / (365*60*60*24));

    $months = floor(($diff - $years * 365*60*60*24) / (30*60*60*24));

    $days = floor(($diff - $years * 365*60*60*24 - $months*30*60*60*24) / (60*60*24));

    $hours = floor(($diff - $years * 365*60*60*24
           - $months*30*60*60*24 - $days*60*60*24)
                                       / (60*60));

    $minutes = floor(($diff - $years * 365*60*60*24
             - $months*30*60*60*24 - $days*60*60*24
                              - $hours*60*60)/ 60);

    $seconds = floor(($diff - $years * 365*60*60*24
             - $months*30*60*60*24 - $days*60*60*24
                    - $hours*60*60 - $minutes*60));

    /*
    printf("%d years, %d months, %d days, %d hours, "
         . "%d minutes, %d seconds", $years, $months,
                 $days, $hours, $minutes, $seconds);
    */

    $out = "";
    if($years > 0 ) { $out .= "$years years, "; }
    if($months > 0 ) { $out .= "$months months, "; }
    if($days > 0 ) { $out .= "$days days, "; }
    if($hours > 0 ) { $out .= "$hours hours, "; }
    if($minutes > 0 ) { $out .= "$minutes minutes, "; }
    if($seconds > 0 ) { $out .= "$seconds seconds, "; }
    $out = rtrim($out,", ");
    return $out;

  }

$template_result = " ";

$date1 = "2021-01-01 09:00:00";
$date2 = "2021-05-04 11:14:21";
$show_date_diff = show_date_diff($date1,$date2);
$template_result .= "<br />Date Diff - $date1, $date2<br />";
$template_result .= $show_date_diff;


$date1 = "2014-01-01 08:00:00";
$date2 = "2021-05-04 11:14:21";
$show_date_diff = show_date_diff($date1,$date2);
$template_result .= "<br />Date Diff 2 - $date1, $date2<br />";
$template_result .= $show_date_diff;