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', 'ge8ih1q6l2h1e47vf5i4bsuqq5', '18.232.53.231', '1566527958', '1566527958', '/products_new.php')

[XT SQL Error]