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', 'nn30fd118prota1saihh83nh53', '216.73.216.80', '1751324781', '1751324781', '/product_info.php?info=p6_100-Party-Teller.html&XTCsid=ce6fa9b759d77118271f618728195fcf')

[XT SQL Error]