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', '0b33e0331aa4f1854a4a43b57430bc59', '216.73.216.190', '1776277375', '1776277375', '/shop/index.php?cat=c11_.html')

[XT SQL Error]