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', 'agpckacrue4v1b6n43r4p8ub44', '216.73.216.145', '1778470075', '1778470075', '/index.php?XTCsid=dc3b0270c322cee1fc32256197e30efa')

[XT SQL Error]