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', 'fcfflcl56fevvbcfiel0nlubb1', '216.73.216.244', '1752214857', '1752214857', '/shop_content.php?coID=3&XTCsid=e9d124d75edbd4a3c97ff72681eedadb')

[XT SQL Error]