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', '5q5uf3i8kgr9d3i73krdq7k3s4', '216.73.216.9', '1758150584', '1758150584', '/shop_content.php?XTCsid=679e5364f8ebcbd98062f6d07b727e6d&coID=3')

[XT SQL Error]