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', 'qtnbrguhm1lpd98hb8agccqni0', '216.73.216.118', '1761374805', '1761374805', '/shop_content.php?XTCsid=679e5364f8ebcbd98062f6d07b727e6d&coID=7')

[XT SQL Error]