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', 'o917487v2a4niee3i3s7hu0l16', '216.73.216.113', '1752884279', '1752884279', '/shop_content.php?coID=4&XTCsid=4299a8bbf7f56cb5a06703b866244eb3')

[XT SQL Error]