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', 'gkbcm379l7b09h9h58hvr91ik3', '216.73.216.63', '1774451087', '1774451087', '/index.php?XTCsid=38f09672db884903e3803adf9d076819&cat=c13_Accessoires.html')

[XT SQL Error]