1366 - Incorrect integer value: '' for column `pella-ware`.`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', '2c9e4101a8e9752b2c8ffe6240db6c04', '3.149.252.37', '1713856842', '1713856842', '/shopping_cart.php?language=de')

[XT SQL Error]