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', 'fpdg8t87puc3r97ea7bhgitpo0', '216.73.216.9', '1758084516', '1758084516', '/product_info.php?XTCsid=ec445a26a1be1b54e711876da9fff244&info=p17_20-Servietten.html')

[XT SQL Error]