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', '553valmb5mpl6h5vtkas8p33d7', '216.73.216.155', '1767611228', '1767611228', '/shop_content.php?XTCsid=85f438a686cbfb5e3ea5e5d6b9611958&coID=3')

[XT SQL Error]