get in stock product list

Question

I am creating a page that display in stock products. I am using

Mage::getSingleton('cataloginventory/stock')->addInStockFilterToCollection($this->_productCollection);

in my custom product list block extending Mage_Catalog_Block_Product_List. But this code includes products that have qty=0. If i added filter qty>0, it will also remove configurable product that have qty=0 BUT have simple(child,associated) products with qty > 0. How do I solve this?

Basically, from this current list, i want to filter out simple product that have qty < 1.

Answer 1

I solved this by adding

            if($isReadystock){
            $this->_productCollection->addAttributeToFilter(
                'status',
                array('eq' => Mage_Catalog_Model_Product_Status::STATUS_ENABLED)
            );
            $this->_productCollection->getSelect()->columns(
                array(
                    'qty1' => 'IFNULL(inventory1.qty,0)',
                    'qty2' => 'IFNULL(inventory2.qty,0)',
                    'qty'  => '(IFNULL(inventory1.qty,0)  + IFNULL(inventory2.qty,0) )',
                )
                );
            $this->_productCollection->getSelect()->joinLeft(array("inventory2" => 'cataloginventory_stock_item'), "e.entity_id = inventory2.product_id", null);
            $subquery = "SELECT `cpr`.`parent_id`,  `at_inventory_in_stock`.`qty`  from `catalog_product_relation` AS `cpr` LEFT JOIN `cataloginventory_stock_item`  AS `at_inventory_in_stock` ON `at_inventory_in_stock`.`product_id`=`cpr`.`child_id` INNER JOIN `catalog_product_entity_int` AS `at_status` ON `at_status`.`entity_id`=`cpr`.`child_id` AND `at_status`.`attribute_id`=96 WHERE qty>0 AND `at_status`.`value`=1 GROUP BY parent_id";
            $this->_productCollection->getSelect()->joinLeft(array("inventory1" => new Zend_Db_Expr('('.$subquery.')')), "e.entity_id = inventory1.parent_id", null);
            $this->_productCollection->getSelect()->where('(IFNULL(inventory1.qty,0)  + IFNULL(inventory2.qty,0) )>0');
        }