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', '8jdki3l1gf9bnckt4ls27t9d95', '216.73.217.152', '1790989826', '1790989826', '/product_info.php?XTCsid=d163dd0fc0b54bf3066f85422c77e00a&info=p19_10-Paper-Plates.html&language=de')

[XT SQL Error]