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', '04v3b08k6k7ahd5c04sup00b04', '216.73.216.110', '1752047435', '1752047435', '/product_info.php?info=p14_65-drinking-cups-1-2-Liter.html&XTCsid=38f09672db884903e3803adf9d076819')

[XT SQL Error]