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', 'jm3n7j4lsvcpgosg2gk6grcds1', '216.73.216.244', '1752215858', '1752215858', '/product_info.php?language=en&info=p19_10-Paper-Plates.html&XTCsid=85f438a686cbfb5e3ea5e5d6b9611958')

[XT SQL Error]