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', '43ta6432bhv655dlf8i28ie643', '216.73.216.63', '1773801051', '1773801051', '/index.php?XTCsid=2fbe11bab8d79764eb267b19bf7c8336')

[XT SQL Error]