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', 's3c2ickc0pqe2is8ah66v0atv3', '216.73.216.165', '1752390992', '1752390992', '/shop_content.php?coID=4&XTCsid=33509f1bee4ee2cbb673a74e5faae0d4')

[XT SQL Error]