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', 'r65sq2ll9fv2ibbkjd3ncs0ve1', '216.73.216.147', '1780977366', '1780977366', '/products_new.php?XTCsid=72205775904d1a5c41b590dd7b5ff1d6&language=en')

[XT SQL Error]