PHP Time calculation - php

Question

Say I have the following 2 dates, a start date and end date:
Year-Month-Day Hours:Minutes:Seconds
Start Date: 2010-12-03 14:04:41
Expiry Date: 2010-12-06 12:59:59
How could I, using PHP subtract the two dates and be left with something like:
Difference: -3 days, 2 minutes and 18 seconds (If expiry date is past 3 days for example).

Answer 1

http://www.php.net/manual/en/datetime.diff.php
<?php
$datetime1 = date_create('2009-10-11');
$datetime2 = date_create('2009-10-13');
$interval = date_diff($datetime1, $datetime2);
echo $interval->format('%R%d days');
//result will be +2 days
?>
I hope that is what you are looking for.

Answer 2

This is based on numerous online examples; you'll see similar code all around if you get your google on.
function timeSince($dateFrom, $dateTo) {
// array of time period chunks
$chunks = array(
array(60 * 60 * 24 * 365 , 'year'),
array(60 * 60 * 24 * 30 , 'month'),
array(60 * 60 * 24 * 7, 'week'),
array(60 * 60 * 24 , 'day'),
array(60 * 60 , 'hour'),
array(60 , 'minute'),
);
$original = strtotime($dateFrom);
$now = strtotime($dateTo);
$since = $now - $original;
$message = ($now < $original) ? '-' : null;
// If the difference is less than 60, we will show the seconds difference as well
if ($since < 60) {
$chunks[] = array(1 , 'second');
}
// $j saves performing the count function each time around the loop
for ($i = 0, $j = count($chunks); $i < $j; $i++) {
$seconds = $chunks[$i][0];
$name = $chunks[$i][1];
// finding the biggest chunk (if the chunk fits, break)
if (($count = floor($since / $seconds)) != 0) {
break;
}
}
$print = ($count == 1) ? '1 ' . $name : $count . ' ' . $name . 's';
if ($i + 1 < $j) {
// now getting the second item
$seconds2 = $chunks[$i + 1][0];
$name2 = $chunks[$i + 1][1];
// add second item if it's greater than 0
if (($count2 = floor(($since - ($seconds * $count)) / $seconds2)) != 0) {
$print .= ($count2 == 1) ? ', 1 ' . $name2 : ', ' . $count2 . ' ' . $name2 . 's';
}
}
return $message . $print;
}
It was intended to show the difference between a given time and the current time, but I've made slight changes to show the difference between two times instead. You may wish to change the output from a postfix of ' ago' to a prefix of 'Difference: '.