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', 's16nuu5atmp6tpr5pbpa3h6tk3', '216.73.216.63', '1774024514', '1774024514', '/product_info.php?XTCsid=7c604026da355cfd6a094c68b431572d&info=p14_65-drinking-cups-1-2-Liter.html')

[XT SQL Error]