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', 'nevjlek7v4mo08uel0ufurg2j5', '216.73.216.211', '1767926586', '1767926586', '/index.php?XTCsid=d3edd3fcb58e1977f2007b47233256d4')

[XT SQL Error]