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', '9ogdfcegjp97fo71qjtofkoe75', '216.73.216.139', '1770966651', '1770966651', '/index.php?XTCsid=4299a8bbf7f56cb5a06703b866244eb3&cat=c11_Room-decorations.html')

[XT SQL Error]