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', 'qajre5cdon22vh40j5dfvqtpq7', '216.73.216.87', '1765635214', '1765635214', '/index.php?XTCsid=433c35e5561812c6a45579d228f7386a')

[XT SQL Error]