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', 'bdcu91sfbqd5t836095ie69n50', '216.73.216.47', '1758041477', '1758041477', '/product_info.php?info=p539_405816-Pfostentraeger-Dorn-zum-Aufschrauben-verstellbar-80x80.html')

[XT SQL Error]