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', 'f5r71atip94prp8vhhr9mk0e40', '216.73.216.147', '1751966854', '1751966854', '/index.php?XTCsid=61ba925c46144fb6a3eaf868339da23b')

[XT SQL Error]