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', '8dsf7rvskvq454v4dliuqfasb4', '216.73.216.113', '1752884174', '1752884174', '/product_info.php?info=p19_10-Paper-Plates.html&XTCsid=75dc59d6a30660e0992222d2318ca53e')

[XT SQL Error]