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', '4b1ln2o2tmh238eh0uvauq2457', '216.73.216.178', '1769078805', '1769078805', '/product_info.php?XTCsid=cdfc0f2ea8be6cebe1f6056b0a37d83f&info=p16_Octoberfest-CD.html')

[XT SQL Error]