1366 - Incorrect integer value: '' for column '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', 'm8pf1a2tj0jvg3f6nvcmea8606', '2600:1f28:365:80b0:6333:a944:b99e:9c59', '1791476359', '1791476359', '/')

[XT SQL Error]