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', '5nkt2rre4vugi9h6khrkt7brc7', '216.73.216.110', '1752060147', '1752060147', '/product_info.php?info=p16_Octoberfest-CD.html&XTCsid=e65207aee44f142683bacdd3544c84a8')

[XT SQL Error]