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', 'g8f7k7jq5jfbeqrep3s9dcla81', '216.73.216.9', '1758172368', '1758172368', '/index.php?XTCsid=4299a8bbf7f56cb5a06703b866244eb3&cat=c8_Disposable-tableware.html')

[XT SQL Error]