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', 'tcj0lsspo1u6jg1jvitpkkbrt1', '216.73.216.128', '1770282583', '1770282583', '/product_info.php?info=p26_Ueberhitzungsschutzschalter-fuer-E-Futterdaempfer.html')

[XT SQL Error]