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', '0ttp3vgq24h6baf1cblog4usb5', '216.73.216.125', '1786830174', '1786830174', '/shop_content.php?XTCsid=363052f8eb28c495db1ddeca225278d6&coID=8')

[XT SQL Error]