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', '3j8p2aslip638ktg8692ppp2c7', '3.133.123.217', '1738996144', '1738996144', '/index.php?XTCsid=mgdqk1fhm8rf8rhaciivk3tpt2&cat=c21_Handy---Smartphone-Akku.html')

[XT SQL Error]