*/ class Collection extends \Magento\Framework\Model\ResourceModel\Db\Collection\AbstractCollection { /** * Resource initialization * * @return void */ protected function _construct() { $this->_init( \Magento\Tax\Model\Sales\Order\Tax::class, \Magento\Tax\Model\ResourceModel\Sales\Order\Tax::class ); } /** * Retrieve order tax collection by order identifier * * @param \Magento\Framework\DataObject $order * @return \Magento\Tax\Model\ResourceModel\Sales\Order\Tax\Collection */ public function loadByOrder($order) { $orderId = $order->getId(); $this->getSelect()->where('main_table.order_id = ?', (int)$orderId)->order('process'); return $this->load(); } }