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', 'a42ebdfe3b0dc04eaa32262c656f86cb', '3.15.156.140', '1713933323', '1713933323', '/account.php?language=de')

[XT SQL Error]