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', '1dqmjrqtt6g09ftg2hnuafflr2', '216.73.216.110', '1752058642', '1752058642', '/products_new.php?XTCsid=3547ee950f9337e348e5e07def1466f0')

[XT SQL Error]