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', 'l7p0e1cad7sm2plco8tsve1e10', '3.140.186.66', '1746975739', '1746975739', '/xtshop/product_info.php?info=p403_.html')

[XT SQL Error]