1366 - Incorrect integer value: '' for column `hbl_shop`.`whos_online`.`customer_id` at row 1

insert into whos_online (customer_id, full_name, session_id, ip_address, time_entry, time_last_click, last_page_url) values ('', 'Guest', 'n39m5tshqpqr9ru3mu7fj5vf45', '216.73.216.29', '1768870380', '1768870380', '/product_info.php?info=p548_Druckfester-Badeoberofen-Edelstahl-mit-Waermetauscher-100-Liter.html')

[XT SQL Error]