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', '7d7c43eb6bf3ddda2ed5d1a2e93669c2', '3.147.86.27', '1744901534', '1744901534', '/shop/index.php')

[XT SQL Error]