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', 'ubj61hksir07l9q70k92q08oa3', '216.73.216.147', '1751764684', '1751764684', '/products_new.php?XTCsid=ec5c494959fcca91c837d8ac4294232c')

[XT SQL Error]