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', 'i8qh649k8j93no726e9ef489p4', '216.73.216.87', '1765725740', '1765725740', '/index.php?XTCsid=1455d70b156c4853db961f68b595bbe7&cat=c5_Crockery.html')

[XT SQL Error]