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', 'u14rcbg6mpknaq5djp065jrjc0', '216.73.216.60', '1760385355', '1760385355', '/shop_content.php?XTCsid=a63f52844b6e675f480eaf86612536c2&coID=2')

[XT SQL Error]