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', '8b94imhekgktn9o83olfoieli2', '216.73.216.46', '1767827593', '1767827593', '/product_info.php?info=p520_Mischung-fuer-Kurzschnabeltauben-25kg-K.html')

[XT SQL Error]