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', '2dj1j5bv1nblt7gjg7lu8k68v1', '216.73.217.78', '1791237654', '1791237654', '/product_info.php?XTCsid=1455d70b156c4853db961f68b595bbe7&info=p21_Paper-tablecloth-10-meters.html')

[XT SQL Error]