1366 - Incorrect integer value: '' for column `mapshopatlogis`.`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', '2dc01e6dfcc1eab8c03e2ee169901811', '216.73.216.8', '1758027912', '1758027912', '/shopping_cart.php/language/de')

[XT SQL Error]