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', '75ea737e9bc64c0fa6d8a4ad6688cd97', '54.158.251.104', '1638801186', '1638801186', '/shop/index.php')

[XT SQL Error]