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', 'dsj81j7pacbap6mfipj5alum94', '216.73.216.253', '1782005466', '1782005466', '/index.php?XTCsid=ca28ab8f46bb6e791b42fe9b92719761&cat=c5_Crockery.html')

[XT SQL Error]