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', 'qfpj22898g9k1vv02vajv559i0', '216.73.216.9', '1757977642', '1757977642', '/index.php?XTCsid=15cbbc13723f7bc63afaf1294f637517&cat=c2_Decoration.html')

[XT SQL Error]