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', '1991sr6ee8c69nil3pv74771c5', '3.140.196.222', '1738998634', '1738998634', '/index.php?XTCsid=8e9c41f9ih262sbjeph8l1hut4&cat=c920_Roboter---Staubsauger-Zubeh--r.html')

[XT SQL Error]