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', 'uvhsqn61dp67h31nv4ni15kbi1', '216.73.216.165', '1752389930', '1752389930', '/index.php?XTCsid=433c35e5561812c6a45579d228f7386a')

[XT SQL Error]