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', 'hi43gbdhj0tuilff1as3nuej51', '216.73.217.93', '1784526529', '1784526529', '/index.php?XTCsid=7c604026da355cfd6a094c68b431572d&cat=c12_Music.html')

[XT SQL Error]