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', '1jrpqkl3gt79jebob7ah6bge56', '3.22.70.102', '1746783548', '1746783548', '/xtshop/product_info.php?info=p502_.html')

[XT SQL Error]