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', 'rbotrakk59co74ugr2fg5gh3c0', '216.73.216.40', '1773617303', '1773617303', '/index.php?XTCsid=07630e5b15e9155d8246af3ee660ca0e&cat=c2_Decoration.html')

[XT SQL Error]