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', '566jb98g5ja5j23v5sdeoc6l92', '216.73.216.113', '1775361359', '1775361359', '/product_info.php?XTCsid=792dd2eece839333bab562194e3fb545&info=p17_20-Tissue-Napkins.html')

[XT SQL Error]