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', 'ouoprp5s0qru3uap7pr67em5c3', '216.73.216.167', '1762527968', '1762527968', '/index.php?XTCsid=7721da20a623cbf55c11923452088e5a')

[XT SQL Error]