1) Yes it is possible to import from itself (it's called re-imports). For further info, see: See http://comtrade.un.org/kb/article.aspx?id=10038 or go find International Merchandise Trade Statistics Concepts & Definitions Rev.2 http://comtrade.un.org/kb/article.aspx?id=10173 2) UN Comtrade does not provide option to keep the missing values. ...