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', '3l6c8fte70oj9pp76d6l31ac95', '216.73.216.9', '1758162377', '1758162377', '/product_info.php?XTCsid=0832187515ca706758d8e1ce01e34faf&info=p2_Bavarian-Pennant-Chain.html')

[XT SQL Error]