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', 'hfttkvqem01o20u2e18k5ua471', '216.73.216.80', '1751325559', '1751325559', '/shop_content.php?coID=1&XTCsid=a0c8d0b3d08cb472c84559a313755d47')

[XT SQL Error]