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', '293b6c3cbcb016b431e551123953a4e8', '216.73.216.213', '1767295227', '1767295227', '/shop/product_info.php?info=p130_.html')

[XT SQL Error]