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', 'a9gufqlg7r04cfo8brugcaami5', '216.73.216.180', '1766054066', '1766054066', '/index.php?XTCsid=3e3fcef0642c69bbf707de3c0bc1cf9c&cat=c2_Decoration.html')

[XT SQL Error]