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', '2igpm3e2a9s61v5to8i5k06p47', '216.73.216.7', '1758254367', '1758254367', '/product_info.php?XTCsid=ec445a26a1be1b54e711876da9fff244&info=p15_25-balloons.html&language=en')

[XT SQL Error]