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', 'e4vb7gfsn10ig08jqh3vmr1qo7', '216.73.216.80', '1751325693', '1751325693', '/shop_content.php?coID=4&XTCsid=5452c15f57f0ea9ce022f9dc9cfaa045')

[XT SQL Error]