esto me lo encontré hace mucho, aun no lo he probado pero igual te vale:
Código PHP:
function datediff($interval, $datefrom, $dateto, $using_timestamps = false)
{ /* $interval can be:
yyyy - Number of full years
q - Number of full quarters
m - Number of full months
y - Difference between day numbers
(eg 1st Jan 2004 is "1", the first day. 2nd Feb 2003 is "33". The datediff is "-32".)
d - Number of full days
w - Number of full weekdays
ww - Number of full weeks
h - Number of full hours
n - Number of full minutes
s - Number of full seconds (default) */
if (!$using_timestamps)
{
$datefrom = strtotime($datefrom, 0);
$dateto = strtotime($dateto, 0);
}
$difference = $dateto - $datefrom; // Difference in seconds
switch($interval) {
case 'yyyy': // Number of full years
$years_difference = floor($difference / 31536000);
if (mktime(date("H", $datefrom), date("i", $datefrom), date("s", $datefrom), date("n", $datefrom), date("j", $datefrom), date("Y", $datefrom)+$years_difference) > $dateto)
{ $years_difference--; }
if (mktime(date("H", $dateto), date("i", $dateto), date("s", $dateto), date("n", $dateto), date("j", $dateto), date("Y", $dateto)-($years_difference+1)) > $datefrom)
{ $years_difference++; }
$datediff = $years_difference;
break;
case "q": // Number of full quarters
$quarters_difference = floor($difference / 8035200);
while (mktime(date("H", $datefrom), date("i", $datefrom), date("s", $datefrom), date("n", $datefrom)+($quarters_difference*3), date("j", $dateto), date("Y", $datefrom)) < $dateto)
{ $months_difference++; }
$quarters_difference--;
$datediff = $quarters_difference;
break;
case "m": // Number of full months
$months_difference = floor($difference / 2678400);
while (mktime(date("H", $datefrom), date("i", $datefrom), date("s", $datefrom), date("n", $datefrom)+($months_difference), date("j", $dateto), date("Y", $datefrom)) < $dateto)
{ $months_difference++; }
$months_difference--;
$datediff = $months_difference;
break;
case 'y': // Difference between day numbers
$datediff = date("z", $dateto) - date("z", $datefrom);
break;
case "d": // Number of full days
$datediff = floor($difference / 86400);
break;
case "w": // Number of full weekdays
$days_difference = floor($difference / 86400);
$weeks_difference = floor($days_difference / 7); // Complete weeks
$first_day = date("w", $datefrom);
$days_remainder = floor($days_difference % 7);
$odd_days = $first_day + $days_remainder; // Do we have a Saturday or Sunday in the remainder?
if ($odd_days > 7)
{ // Sunday
$days_remainder--;
}
if ($odd_days > 6)
{ // Saturday
$days_remainder--;
}
$datediff = ($weeks_difference * 5) + $days_remainder;
break;
case "ww": // Number of full weeks
$datediff = floor($difference / 604800);
break;
case "h": // Number of full hours
$datediff = floor($difference / 3600);
break;
case "n": // Number of full minutes
$datediff = floor($difference / 60);
break;
default: // Number of full seconds (default)
$datediff = $difference;
break;
}
return $datediff;
}