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', '7i2itih383vm8ba8rorkteha13', '18.191.167.138', '1738999311', '1738999311', '/index.php?XTCsid=c8tsstf8ajiodlgrn3rqsr62b1&cat=c538_Gesipa-Werkzeug-Akku.html')

[XT SQL Error]