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', 'nqoe59qfo8h94b40p0ub42v1h1', '216.73.216.167', '1762467923', '1762467923', '/index.php?XTCsid=3b147b8f13a7f162d315476fb5c01d44')

[XT SQL Error]