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', '2ae5f0a649562bd091e9794a205e44f3', '216.73.217.75', '1789292299', '1789292299', '/shop/product_info.php?info=p36_.html')

[XT SQL Error]