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', 'nuod0qerqe7f6v4gqvi438lmq7', '216.73.216.147', '1781024095', '1781024095', '/shop_content.php?XTCsid=bdaba9e3c5005b887aab6c0c38edc3a6&coID=1')

[XT SQL Error]