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', 'e3ac81b7244e73c4ffe175ce91049796', '216.73.217.75', '1789292388', '1789292388', '/shop/product_info.php?info=p116_.html')

[XT SQL Error]