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', '9ungpei2qj6k0p90p81m05vcl5', '3.137.162.63', '1746779153', '1746779153', '/xtshop/index.php')

[XT SQL Error]