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', 'cia4pvlkvat4iindf92p7lu7k3', '216.73.216.110', '1752054685', '1752054685', '/index.php?cat=c12_Musik.html&XTCsid=ce6fa9b759d77118271f618728195fcf')

[XT SQL Error]