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', 'qh9ar80qncqf6q35ocfb1fkk71', '216.73.216.70', '1752612448', '1752612448', '/index.php?language=en&XTCsid=7c604026da355cfd6a094c68b431572d')

[XT SQL Error]