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', 's04jl154obk1r01a4kdq5shtl4', '18.191.31.223', '1738999772', '1738999772', '/index.php?XTCsid=c8tsstf8ajiodlgrn3rqsr62b1&cat=c31_Batterien.html')

[XT SQL Error]