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', 'j6hf1hvkvi7162o7c3m0c0jf74', '216.73.217.92', '1777199364', '1777199364', '/index.php?XTCsid=4635a65037080db684b109117d2fc14c')

[XT SQL Error]