1366 - Incorrect integer value: '' for column `agentur`.`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', 'a1l45m976kouoom04898mt2d10', '3.235.101.50', '1601417842', '1601417842', '/index.php?cat=c90_Heino-Konzert.html&XTCsid=l56nbturorq4sho45n10a33330')

[XT SQL Error]