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', 'uljms1a2i86s1vettrhsk8fns0', '216.73.216.180', '1766856970', '1766856970', '/product_info.php?XTCsid=3f98699a7205aa16d7f8014dc7c0d34a&info=p19_10-Paper-Plates.html')

[XT SQL Error]