mysql join update

SELECT
 CONCAT(
'UPDATE free_for_demo_orders  SET product_id=',
product_id,
',order_created_time=',
'"',
TIMESTAMPADD(HOUR, 8, sales_order.created_at),
'" WHERE order_id=',
entity_id,
';'
),
 `entity_id`,
 
  customer_id,
  `customer_email`,
  quote_id,
  sales_order.store_id,
  product_id,
  TIMESTAMPADD(HOUR, 8, sales_order.created_at),
  TIMESTAMPADD(HOUR, 8, sales_order.created_at)
FROM
  `sales_flat_order` AS sales_order
LEFT JOIN  `sales_flat_order_item` ON  entity_id=order_id
WHERE  STATUS <> 'canceled' AND grand_total=10 AND price  = 0