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', '26lp7or4r88mu6ogg8qlpib1h5', '216.73.216.116', '1782563032', '1782563032', '/index.php?XTCsid=78d104da211603518fe01de887166f28')

[XT SQL Error]