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', 'afce415b2036facb354ccc87578667a4', '3.145.183.137', '1713519190', '1713519190', '/redirect.php?action=product&id=31')

[XT SQL Error]