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', 'gq4gotmcv137jmd8po33mns0d6', '216.73.216.176', '1762237387', '1762237387', '/shop_content.php?XTCsid=7f3d063595fd0cf7dd24ecea4b1409d6&coID=8')

[XT SQL Error]