Another variation on the "time ago" PHP function, use MySQL's datetime field type

I was recently looking at writing a function to format the comment post times in the ever trendy "time ago" style... such as;

Matt posted 6 days 3 hours ago

Naturally I first scoured the web for an appropriate existing PHP function, and I came across this one; http://wessite.com/item/2008/11/digg-like-time-ago-php-function (dead link).

Quite useful and fairly complete, but there were a few things I wanted to change, so I've hacked it up and remixed it here to accept a MySQL datetime field type result and then format the output like mentioned above. I also added weeks, months, years, and decades to the function to carry it as far out as anyone would possibly want it to go.

If you're using sNews and want to use this for your comments, simply follow these 2 quick steps.

Step 1) As always, BACK-UP your snews.php file and work off a copy. Now simply copy the function below into your snews.php file, right above the closing php tag;

// DISPLAYS COMMENT POST TIME AS "1 year, 1 week ago" or "5 minutes, 7 seconds ago", etc...
function time_ago($date,$granularity=2) {
    $date = strtotime($date);
    $difference = time() - $date;
    $periods = array('decade' => 315360000,
        'year' => 31536000,
        'month' => 2628000,
        'week' => 604800, 
        'day' => 86400,
        'hour' => 3600,
        'minute' => 60,
        'second' => 1);
    if ($difference < 5) { // less than 5 seconds ago, let's say "just now"
        $retval = "posted just now";
        return $retval;
    } else {                            
        foreach ($periods as $key => $value) {
            if ($difference >= $value) {
                $time = floor($difference/$value);
                $difference %= $value;
                $retval .= ($retval ? ' ' : '').$time.' ';
                $retval .= (($time > 1) ? $key.'s' : $key);
                $granularity--;
            }
            if ($granularity == '0') { break; }
        }
        return ' posted '.$retval.' ago';      
    }
}

Step 2) Now find the function comment, and comment out the existing date format and add the highlighted code like below;

while ($r = mysql_fetch_array($result)) {
    //$date = date($date_format, strtotime($r['time']));
    $date = time_ago($r['time']);
    $commentNum = $offset + $ordinal;

That should do it, now your comment times should be formatted by "time ago". I just thought it may be useful to someone else looking for the functionality.