แนะนำเอาค่าในฟิลมา - กันหน่อยครับ ควรทำแบบไหน ให้ค่าออกมาแล้วตรง

funciton cv2diffStr( $diff){
   $sec = $diff<0? -$diff : $diff;
   $_1min = 60;
   $_1hour = 60 * $_1min;
   $_1day = 24 * $_1hour;
   $d = floor( $sec/ $_1day); $sec-= $d * $_1day;
   $h = floor( $sec/ $_1hour); $sec-= $h * $_1hour;
   $m = floor( $sec/ $_1min); $sec-= $m * $_1min;
   return  ($idf<0? ' - ' : '' ) . $d . ' ' . $h . ':' . $m . ':' . $sec;
}
$last = '';
while(.....){
    echo ($last == '' ? ' - ' :  cv2diffStr(strtotime($last) - strtotime($r['time']));
    $last = $r['time'];
}

$last = '';
while(.....){
    echo ($last == '' ? ' - ' :  cv2diffStr(strtotime($last) - strtotime($r['time']));
    $last = $r['time'];
}