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', 'vefnr0um84tgf9a1qbgpv1pgj1', '3.85.92.139', '1561469449', '1561469449', '/index.php/cat/c4_Tec-Wings.html')

[XT SQL Error]