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', 'uto0qd5vbqk3psap6tl2sgtk96', '216.73.216.80', '1751317105', '1751317105', '/popup_content.php?coID=1&XTCsid=adc8c520bddaa9e02a40df1e2a90f128')

[XT SQL Error]