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', 'q31t88bh7hubi3n2gjn0p9d0f3', '2600:1f28:365:80b0:f081:ac47:f724:b689', '1781522190', '1781522190', '/')

[XT SQL Error]