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', 'do4u0458tp2hr2oh37irl1htm4', '216.73.216.165', '1752308376', '1752308376', '/index.php?cat=c9_Tabledeko.html&XTCsid=a61b1c7c4e21580bd9d4e85a32d692bc')

[XT SQL Error]