Shipment是EAV模型，默认不会选出order_id信息,因此需要使用使用addAttributeToSelect方法，代码如下:
$collection = Mage::getModel('sales/order_shipment')->getCollection()->addAttributeToSelect('order_id')->addAttributeToFilter('increment_id', '100000002'); foreach($collection AS $c) { echo 'Order Id : ' . $c->getOrder()->getId(); break; }
