1366 - Incorrect integer value: '' for column `wwwmodellbahn_diskont1`.`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', 'qgfld7nq5l1e7af7sob3s2qnj2', '18.232.171.18', '1566444929', '1566444929', '/index.php?cat=c69_Start--und-Zugsets.html')

[XT SQL Error]