Does sales_shipping_aggregated relate to the sale_flat_order table? How?

Question

I see that there are not any relationships from sales_shipping_aggregated to the sales_flat_order table. I'm trying to determine if there is a relationship to anything other than sales_shipping_aggregated_order.

What is the purpose of these two tables (ssa and ssao) and do they relate to the individual orders at all?

Background: I'm trying to merge two different Magento stores into one instance. Needing to migrate data.

Answer 1

Those tables are use for reporting (see Admin -> report -> sales -> shipping)

See

/app/code/core/Mage/Adminhtml/Block/Report/Sales/Shipping/Grid.php

class Mage_Adminhtml_Block_Report_Sales_Shipping_Grid extends Mage_Adminhtml_Block_Report_Grid_Abstract
{
    ...

    public function getResourceCollectionName()
    {
        return ($this->getFilterData()->getData('report_type') == 'created_at_shipment')
            ? 'sales/report_shipping_collection_shipment'
            : 'sales/report_shipping_collection_order';
    }

/app/code/core/Mage/Sales/Model/Resource/Report/Shipping/Collection/Shipment.php

class Mage_Sales_Model_Resource_Report_Shipping_Collection_Shipment
    extends Mage_Sales_Model_Resource_Report_Shipping_Collection_Order
{
    /**
     * Initialize custom resource model
     *
     */
    public function __construct()
    {
        $this->setModel('adminhtml/report_item');
        $this->_resource = Mage::getResourceModel('sales/report')->init('sales/shipping_aggregated');
        $this->setConnection($this->getResource()->getReadConnection());
    }
}

/app/code/core/Mage/Sales/etc/config.xml

<sales_resource>
    ....
    <shipping_aggregated>
       <table>sales_shipping_aggregated</table>
    </shipping_aggregated>
    <shipping_aggregated_order>
        <table>sales_shipping_aggregated_order</table>
    </shipping_aggregated_order>