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', 'no1i6812v308noha993tfb45v4', '216.73.216.147', '1751837935', '1751837935', '/index.php?language=en&XTCsid=38717c4dd62e88001622b2c7b8b8372a')

[XT SQL Error]