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', 'mv31oq7vbqtli4oqcu5v8cak56', '3.22.120.195', '1746975420', '1746975420', '/xtshop/product_info.php?info=p1006_.html')

[XT SQL Error]