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', '2f2cd8a8496c551a0a2eeafa1714f744', '18.191.166.168', '1747955048', '1747955048', '/shop/index.php')

[XT SQL Error]