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', 'cuor3ri8uprl0lsp17ngmcc8l2', '216.73.216.80', '1751326920', '1751326920', '/product_info.php?info=p17_20-Tissue-Napkins.html&XTCsid=3547ee950f9337e348e5e07def1466f0')

[XT SQL Error]