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', '8gcrsq9d8s7dp1m7ja30f2evg3', '35.175.113.29', '1581943174', '1581943174', '/')

[XT SQL Error]