1366 - Incorrect integer value: '' for column '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', 'lqnos96522m8jt4psle4ah2282', '216.73.216.105', '1789797499', '1789797499', '/xtshop/index.php?cat=c5_.html')

[XT SQL Error]