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', 'eeiq2ljoivksimd8qou6g96rd2', '216.73.216.9', '1758150455', '1758150455', '/product_info.php?XTCsid=a63f52844b6e675f480eaf86612536c2&info=p21_Paper-tablecloth-10-meters.html')

[XT SQL Error]