ここでは、まさにそれを行う関数と多くのオプションを確認できます:
http://php.net/manual/es/function.date-diff.php#98615
<?php
/*
* A mathematical decimal difference between two informed dates
*
* Author: Sergio Abreu
* Website: http://sites.sitesbr.net
*
* Features:
* Automatic conversion on dates informed as string.
* Possibility of absolute values (always +) or relative (-/+)
*/
function s_datediff( $str_interval, $dt_menor, $dt_maior, $relative=false){
if( is_string( $dt_menor)) $dt_menor = date_create( $dt_menor);
if( is_string( $dt_maior)) $dt_maior = date_create( $dt_maior);
$diff = date_diff( $dt_menor, $dt_maior, ! $relative);
switch( $str_interval){
case "y":
$total = $diff->y + $diff->m / 12 + $diff->d / 365.25; break;
case "m":
$total= $diff->y * 12 + $diff->m + $diff->d/30 + $diff->h / 24;
break;
case "d":
$total = $diff->y * 365.25 + $diff->m * 30 + $diff->d + $diff->h/24 + $diff->i / 60;
break;
case "h":
$total = ($diff->y * 365.25 + $diff->m * 30 + $diff->d) * 24 + $diff->h + $diff->i/60;
break;
case "i":
$total = (($diff->y * 365.25 + $diff->m * 30 + $diff->d) * 24 + $diff->h) * 60 + $diff->i + $diff->s/60;
break;
case "s":
$total = ((($diff->y * 365.25 + $diff->m * 30 + $diff->d) * 24 + $diff->h) * 60 + $diff->i)*60 + $diff->s;
break;
}
if( $diff->invert)
return -1 * $total;
else return $total;
}
/* Enjoy and feedback me ;-) */
?>