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', 'qhjglq7jttt4qv6fpp269ar850', '216.73.216.167', '1762482143', '1762482143', '/product_info.php?XTCsid=15cbbc13723f7bc63afaf1294f637517&info=p2_Bavarian-Pennant-Chain.html')

[XT SQL Error]