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', 'ji8a226ijfqs8407cotoqu2e03', '3.129.17.245', '1746787134', '1746787134', '/xtshop/index.php?cat=c49_.html')

[XT SQL Error]