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', '1oh3u4j16s5ulselns6p75qop4', '54.167.219.201', '1496148374', '1496148374', '/')

[XT SQL Error]