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', '2abr6lcbfpmq1c8jq4cclcpnk0', '216.73.216.80', '1751321433', '1751321433', '/index.php?XTCsid=88b83a19887b09d0be81a5bc76327077')

[XT SQL Error]