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', '468ad5e0ce687f9aa0040605d8fc118d', '3.144.189.177', '1713509917', '1713509917', '/redirect.php?action=product&id=14')

[XT SQL Error]