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', 'jjt8j7i6707c5k1lpp1npdimt1', '216.73.216.60', '1760694821', '1760694821', '/product_info.php?XTCsid=38717c4dd62e88001622b2c7b8b8372a&info=p16_Octoberfest-CD.html')

[XT SQL Error]