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', 'd823ab6f0cc2cde5a997cb92843752b0', '216.73.216.213', '1767294857', '1767294857', '/shop/index.php?cat=c29_.html')

[XT SQL Error]