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', 'a8c961f83f010c2a1d0c853ff0ea9a5b', '13.58.39.23', '1713931731', '1713931731', '/redirect.php?action=product&id=79')

[XT SQL Error]