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', 're6r7vip3q3crdem1b6m3jub31', '3.133.123.140', '1746762565', '1746762565', '/xtshop/index.php?cat=c72_.html')

[XT SQL Error]