gistfile1.txt

<?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 ;-) */
?>