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', '00i18ks0idhfchh9d0h1b9cci3', '216.73.216.9', '1757727534', '1757727534', '/shop_content.php?XTCsid=0308d34f52db367f9a7068f51bec2a23&coID=1')

[XT SQL Error]