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', '4k0vvtoi4hvnf6aq0tnjce53j0', '216.73.216.9', '1757957379', '1757957379', '/product_info.php?XTCsid=85f438a686cbfb5e3ea5e5d6b9611958&info=p19_10-Paper-Plates.html&language=en')

[XT SQL Error]