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', 'p6au91h4q5pblimaosg26oo1d2', '52.15.53.236', '1746772750', '1746772750', '/xtshop/product_info.php?info=p833_.html')

[XT SQL Error]