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', '9ut669eoks2nqauu8mmksjit10', '216.73.216.63', '1774080300', '1774080300', '/product_info.php?XTCsid=ec23ca965190a8290c666be9c9947acd&info=p7_Garland-13-feet.html')

[XT SQL Error]