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', '3mrkk6qj6c3up0bbj67c6k32d7', '216.73.217.80', '1790182032', '1790182032', '/index.php?XTCsid=80c3e9fc87b53cb0d288d19ef4e9b63c&cat=c11_Room-decorations.html')

[XT SQL Error]