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', '4qap5tftusbse3pjm2sltr19l6', '3.137.210.169', '1746973304', '1746973304', '/xtshop/product_info.php?info=p396_.html')

[XT SQL Error]