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', 's1sap6m06h3oopimo9ctpt6vq5', '216.73.216.15', '1782233166', '1782233166', '/index.php?XTCsid=38f09672db884903e3803adf9d076819&cat=c13_Accessoires.html')

[XT SQL Error]