DB::queryFirstField PHP Method

    public static function queryFirstField()
    {
        $args = func_get_args();
        return call_user_func_array(array(DB::getMDB(), 'queryFirstField'), $args);
    }

 function getPrizeValue($rid = "")
 {
     if (empty($rid)) {
         $rid = $this->raffle_id;
     }
     return DB::queryFirstField("select sum(tp_price)\n                                   from raffle_prizes p, gw2_items i\n                                   where p.item_id = i.id\n                                     and raffle_id = %i", $rid);
 }