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', '9473c638706ecb738afa3f6cc40091c4', '3.133.87.156', '1714166665', '1714166665', '/redirect.php?action=product&id=69')

[XT SQL Error]