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', 'jcvg3t0f8rtetf3e5vjbm35nr4', '216.73.216.7', '1758227780', '1758227780', '/product_info.php?XTCsid=3dfedf8e10ab51b65faa7b7d7332d93a&info=p14_65-drinking-cups-1-2-Liter.html')

[XT SQL Error]