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', '593eiv0i5fr49p0r6qu53ebjn5', '216.73.216.9', '1758181656', '1758181656', '/product_info.php?XTCsid=3dfedf8e10ab51b65faa7b7d7332d93a&info=p18_Fun-Hat.html')

[XT SQL Error]