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', 'mpf6aqbj5fb6hk0hdnhfaq6gm0', '216.73.217.78', '1789830528', '1789830528', '/product_info.php?XTCsid=a63f52844b6e675f480eaf86612536c2&info=p6_100-Paper-Plates.html')

[XT SQL Error]