Filtering a joined column

Question

I am creating a stock report in the admin and have everything working so far, except that I can\'t seem to be able to filter on the joined column.

I have joined the stoc

Answer 1

After join simply use order to sort your result

$collection->getSelect()
    ->join( array('stock'=>'ccmg_cataloginventory_stock_item'), 'e.entity_id = stock.item_id', array('stock.qty'))
    ->order('stock.qty ASC');

Answer 2

After the join, you need to add the joined field to the array _map declared in Varien_Data_Collection_Db, for example:

$this->_map['fields']['stock_qty'] = 'stock.qty';

[edit] As pointed out by @sh4dydud3_88, you can do this:

$collection->addFilterToMap('stock_qty', 'stock.qty');

which will add the field stock_qty for filtering. Then you can filter with

$collection->addFieldToFilter('stock_qty', array('gt', 10));

Another example:

class Company_Mohe_Model_Resource_Im_Collection extends Mage_Core_Model_Resource_Db_Collection_Abstract
{
protected function _construct()
{
    $this->_init('mohe/im');
}  


public function joinIhe()
{
    $this->getSelect()->join(array('ihe' => $this->getTable('mohe/ihe')),
                                  'main_table.mic_inst_id = ihe.im_id',
                                  array('ihe_name'=>'name', 'ihe_ifms_id'=>'ifms_id')); 
    //$this->_map['fields'] = array('ihe_name'=>'ihe.name', 'ihe_ifms_id'=>'ihe.ifms_id'); //incorrect method
    $this->addFilterToMap('ihe_name', 'ihe.name'); //correct method, see comment by @sh4dydud3_88                           
    return $this;
} 
}