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', '724kt02hd4sn5rduok0g6b64j3', '216.73.216.63', '1773798422', '1773798422', '/product_info.php?XTCsid=f6e58886be8011b1d9a8e232c116cb7a&info=p11_Fan-for-decorations.html')

[XT SQL Error]