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', 's6p8vfrqmotr0v973c3hs9kjs5', '54.196.107.247', '1495571501', '1495571501', '/create_account.php')

[XT SQL Error]