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', 'v64s9ip3fdgv5gdnb7sbkpvmc5', '216.73.216.113', '1752884542', '1752884542', '/shop_content.php?coID=8&XTCsid=363052f8eb28c495db1ddeca225278d6')

[XT SQL Error]