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', 'ssf8cof1dacpa2iofhetkll6f5', '216.73.216.60', '1760588843', '1760588843', '/index.php')

[XT SQL Error]