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', '6fc786213a61fd66792a08ada5be2291', '18.190.156.80', '1713607944', '1713607944', '/redirect.php?action=product&id=25')

[XT SQL Error]