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', '3124458dea8e2a2e7f6912caef3c2f74', '216.73.216.208', '1752065285', '1752065285', '/shop/index.php')

[XT SQL Error]