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', '17dffi6b2v2583886eetl8cc37', '216.73.217.93', '1784237890', '1784237890', '/shop_content.php?XTCsid=38f09672db884903e3803adf9d076819&coID=1')

[XT SQL Error]