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', 'tfr1didr9l5jt9gf7r36eb21i7', '216.73.217.10', '1779238470', '1779238470', '/shop_content.php?XTCsid=a61b1c7c4e21580bd9d4e85a32d692bc&coID=7')

[XT SQL Error]