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', 'iufklf3sk8rtp0e7i2t20tsmh7', '216.73.216.80', '1751318705', '1751318705', '/index.php?XTCsid=5feb46637b49384103dccd0839b41d75')

[XT SQL Error]