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', '0rnpor9j4or7seju857art26o5', '18.232.53.231', '1566150538', '1566150538', '/shop_content.php/coID/8/product/Sitemap')

[XT SQL Error]