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', 'go1m43og88oj5d1j1kceu5qtc5', '54.224.85.115', '1529852481', '1529852481', '/shop/')

[XT SQL Error]