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', 'vfhoh5gjg40q7tsm1k6gu91400', '216.73.216.6', '1763153261', '1763153261', '/index.php?XTCsid=4299a8bbf7f56cb5a06703b866244eb3&cat=c11_Room-decorations.html')

[XT SQL Error]