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', 'r1t8q6n0h8esuh66g1g9b8e4f7', '3.85.92.139', '1561472453', '1561472453', '/shop_content.php/coID/8/product/Sitemap')

[XT SQL Error]