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', 'kl378bdcr2gohgvtlkfj13l2g5', '216.73.216.9', '1757730592', '1757730592', '/shop_content.php?XTCsid=ec23ca965190a8290c666be9c9947acd&coID=7')

[XT SQL Error]