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', 'devoi1vo1ef209u8fbiucvbch2', '216.73.216.110', '1752052224', '1752052224', '/products_new.php?XTCsid=e65207aee44f142683bacdd3544c84a8')

[XT SQL Error]