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', 'mk9huqufkfgmi2i0463tvjd6l7', '216.73.216.87', '1765767833', '1765767833', '/index.php?XTCsid=e65207aee44f142683bacdd3544c84a8&cat=c13_Accessoires.html')

[XT SQL Error]