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', 'bm36o18k2tsugn4fjugip3j1m3', '216.73.216.244', '1752216938', '1752216938', '/index.php?cat=c11_Room-decorations.html&XTCsid=f6e58886be8011b1d9a8e232c116cb7a')

[XT SQL Error]