1366 - Incorrect integer value: '' for column `hollen`.`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, http_referer) values ('', 'Guest', 'a7ma0rk5cs0t4199p68t24n9n0', '3.228.11.9', '1597412112', '1597412112', '/', 'Keiner/None')

[XT SQL Error]