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', '2j97e2tob3kt3u3eevm1301t51', '216.73.216.197', '1751511718', '1751511718', '/product_info.php?info=p6_100-Paper-Plates.html&XTCsid=a63f52844b6e675f480eaf86612536c2')

[XT SQL Error]