Сортировка результатов поиска в поисковом модуле

$Search_Controller_Show->modules(
        array(
            3 => array(array('module_id' => 1, 'module_value_type' => 2))
        )
    );

class Search_Controller_Observer
{
    static public function onBeforeExecuteFind($object, $args)
    {
        $args[1]
            ->leftJoin('shop_warehouse_items', 'shop_warehouse_items.shop_item_id', '=', 'search_pages.module_value_id')
            ->groupBy('search_pages.module_value_id')
            ->clearOrderBy()
            ->orderBy(Core_QueryBuilder::expression('SIGN(SUM(`shop_warehouse_items`.`count`))'), 'DESC');
    }
}

Core_Event::attach('Search_Controller_Hostcms.onBeforeExecuteFind', array('Search_Controller_Observer', 'onBeforeExecuteFind'));