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', 'ov4i0t9ai72kf3gbqltesqjh81', '216.73.216.28', '1775847435', '1775847435', '/product_info.php?XTCsid=ec445a26a1be1b54e711876da9fff244&info=p15_25-balloons.html&language=en')

[XT SQL Error]