Products Sold Collection

Question

I'm creating a custom Grid in Adminhtml which is to list all of the items sold in the past 30 days.

I have the Grid setup, with basic product data being filled. However, I need data such as current stock level and custom attributes etc.

I'm a little new to Magento collections and not sure how to use joins etc to build up my desired collection.

Can anyone assist?

protected function _prepareCollection() {

    $collection = Mage::getResourceModel('sales/order_item_collection')
    ->addAttributeToSelect('*')
    ->join('order', 'order_id=entity_id');

    $this->setCollection($collection);
    return parent::_prepareCollection();
}

Answer 1

Magento use Zend_Db_Select select as base. To get just do

$collection->getSelect();

after work with it like with usual Zend_Db_Select