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', '965nhjij6gkrj9ge0mqinkhhj7', '216.73.216.197', '1751518347', '1751518347', '/index.php?XTCsid=e756562afe263dc0073355c2d36026bf')

[XT SQL Error]