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', 'hemf1jubg43o2a6fjv10ihu861', '216.73.216.244', '1752217162', '1752217162', '/index.php?cat=c5_Crockery.html&XTCsid=d0fb6f95a363340d124d7dc76e615e44')

[XT SQL Error]