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', 'kff4rq2e9jd4qr6nric2m8crq1', '216.73.216.7', '1758227155', '1758227155', '/index.php?XTCsid=3547ee950f9337e348e5e07def1466f0&cat=c9_Tabledeko.html')

[XT SQL Error]