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', 'ba0kejsatcmp46pm7to2528064', '216.73.216.197', '1751519890', '1751519890', '/index.php?XTCsid=e867041440a0061f876d1c01655f4c12')

[XT SQL Error]