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', '1foahq82b86lvstsb5fg9pnk52', '216.73.216.130', '1763882861', '1763882861', '/index.php?XTCsid=15cbbc13723f7bc63afaf1294f637517&cat=c12_Music.html')

[XT SQL Error]