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', 'h3hq003u52a34u2kt8ml9iqv54', '216.73.216.23', '1773480553', '1773480553', '/index.php?XTCsid=c60d173e05a16d5feea88bc4b1883fc9')

[XT SQL Error]