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', '5udnkht0j68odkpp2nsdo2r7m1', '216.73.216.47', '1758011993', '1758011993', '/index.php?cat=c20_Kataloge.html')

[XT SQL Error]