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', '4ecs8ppdm7aemiuc6ggg9s0c73', '216.73.216.193', '1792383666', '1792383666', '/shop_content.php?XTCsid=d9aac22dfe7cd4518be7d12dca4112e1&coID=4')

[XT SQL Error]