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', 'vhi9fi2ifsn4l7h3scb9badf41', '216.73.216.9', '1758060911', '1758060911', '/product_info.php?XTCsid=0045c82a20eb26c176bef1fc0ba16df3&info=p19_10-Paper-Plates.html')

[XT SQL Error]