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', '2nkgcto0iql3ni7vha8e8caij6', '216.73.216.130', '1761319739', '1761319739', '/product_info.php?XTCsid=3e3fcef0642c69bbf707de3c0bc1cf9c&info=p2_Bavarian-Pennant-Chain.html')

[XT SQL Error]