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', 'qs914mmsddcql2n3ovlb2m1e00', '216.73.216.118', '1761572715', '1761572715', '/products_new.php?XTCsid=15cbbc13723f7bc63afaf1294f637517&language=de')

[XT SQL Error]