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', '348uun5dvbdfoi91ljp2vu2hs2', '54.82.56.95', '1513263693', '1513263693', '/shop/')

[XT SQL Error]