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', '74vq4bj9q43al7omeqpevsaf72', '216.73.216.28', '1764971891', '1764971891', '/product_info.php?XTCsid=ca28ab8f46bb6e791b42fe9b92719761&info=p9_Paper-Lantern.html')

[XT SQL Error]