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', 'kcl2tcsihjviqpvkdgcnb72743', '216.73.217.25', '1781319500', '1781319500', '/product_info.php?XTCsid=979063553d403df75eb8c32c59325da8&info=p12_33-feet-crape-paper.html')

[XT SQL Error]