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', 'afb459420653951db6dbb68c4a58a7f4', '54.86.180.90', '1711701382', '1711701382', '/redirect.php?action=product&id=23')

[XT SQL Error]