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', 'eb493c0cff8cb515e5398b353fccf795', '216.73.216.190', '1776276153', '1776276153', '/shop/newsletter.php')

[XT SQL Error]