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', 'qqqlqk7bsujeg1vvbboaqkal35', '54.161.79.96', '1498237411', '1498237411', '/nl6.php')

[XT SQL Error]