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', '4bd0ppiilakft40rf7o4v4ijo3', '216.73.217.172', '1790551112', '1790551112', '/index.php?XTCsid=8045f38f0bef4724ff52869f85afd31c')

[XT SQL Error]