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', '4jm7a7sodlvgc77gdlpjcc2jj5', '34.235.143.190', '1560782508', '1560782508', '/')

[XT SQL Error]