1366 - Incorrect integer value: '' for column `CP_as15`.`whos_online`.`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', 'ns9mmc612gei69fj28aouitv27', '18.218.43.201', '1738999538', '1738999538', '/index.php?XTCsid=8e9c41f9ih262sbjeph8l1hut4&cat=c174_Fein-Werkzeug-Akku.html')

[XT SQL Error]