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', 'ne011fs5lf6c8sbep3kjqgljk2', '216.73.216.9', '1757991233', '1757991233', '/product_info.php?XTCsid=38717c4dd62e88001622b2c7b8b8372a&info=p16_Octoberfest-CD.html')

[XT SQL Error]