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', '369gtli039b6fc8nleqi869t94', '216.73.216.113', '1775450872', '1775450872', '/shop_content.php?XTCsid=85f438a686cbfb5e3ea5e5d6b9611958&coID=3')

[XT SQL Error]