$query = ' 
SELECT 
  order_id, 
  create_date, 
  payment_id,
  payment_total, 
  status, 
  ( 
    SELECT 
        GROUP_CONCAT(product_name separator "\n" ) 
    FROM 
        dtb_order_detail 
    WHERE 
        order_id = dtb_order.order_id 
  ) as product_name 
FROM 
  dtb_order 
WHERE 
  del_flg = 0 AND 
  customer_id = ? 
ORDER BY 
  order_id DESC
LIMIT ? OFFSET ?
'; 
return $objQuery->getAll($query,array($customer_id,SEARCH_PMAX, $startno));