| Аргумент | Возможный тип | Описание |
| $transaction_id | — | — |
$qry = $this->db->query("SELECT SUM(`amount`) AS `amount` FROM `" . DB_PREFIX . "paypal_iframe_order_transaction` WHERE `parent_transaction_id` = '" . $this->db->escape($transaction_id) . "' AND `payment_type` = 'refund'");
return $qry->row['amount'];