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', '493b2aa5e362d1f0405a8876488d81c9', '216.73.216.44', '1768638984', '1768638984', '/shopping_cart.php/language/de')

[XT SQL Error]