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', 'kid5ntgnnm0trap3k6rhb32896', '216.73.216.82', '1752530458', '1752530458', '/index.php?cat=c6_Foodstuffs.html&XTCsid=7f3d063595fd0cf7dd24ecea4b1409d6')

[XT SQL Error]