PHP Time calculation

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

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: '.

Answer 2

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.