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', 'm660c7d81rfq17fo3t3qn0vil6', '216.73.216.176', '1762262567', '1762262567', '/popup_content.php?XTCsid=ec23ca965190a8290c666be9c9947acd&coID=1')

[XT SQL Error]