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', 'vn9valt2u713uec6va7hfhffu7', '18.191.240.134', '1738995571', '1738995571', '/index.php?XTCsid=3urkhm9sdqaa68rq8ocuqac7t6&cat=c26_PDA---Handheld-Akku.html')

[XT SQL Error]