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', 'mb3bndlt2a104rp1euoc2un2l5', '216.73.216.15', '1790849454', '1790849454', '/index.php?XTCsid=a63f52844b6e675f480eaf86612536c2&cat=c12_Music.html')

[XT SQL Error]