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', '33791d40b9054a4f3db925d49c878002', '3.87.250.158', '1643064845', '1643064845', '/shop/index.php')

[XT SQL Error]