Voila ma solution que je partage avec vous :
$this->_select = ' p.id_manufacturer as manufacturer , m.name as name, o.date_add as date, product_name, sum(product_quantity) as qty, sum(product_price) as price'; $this->_join = 'LEFT JOIN `'._DB_PREFIX_.'orders` o ON (o.`id_order` = a.`id_order`) LEFT JOIN `'._DB_PREFIX_.'product` p ON (p.`id_product` = a.`product_id`) LEFT JOIN `'._DB_PREFIX_.'manufacturer` m ON (p.`id_manufacturer` = m.`id_manufacturer`) '; $this->_group = 'GROUP BY a.`product_name`'; $this->_orderBy ='price'; $this->_orderWay = 'DESC';
si il y a une autre solution mieux que la mienne je suis la pour la tester