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', 'o03bf0qlcj33h4kr20cvvgh4t0', '100.26.182.28', '1569224863', '1569224863', '/')

[XT SQL Error]