>Naomi >I've faced that many times and I've always wound up looping through the rows of the first data table and adding modified rows to the new data table. > >I tried LINQ several times, but the looping approach always seemed more straightforward. > I found http://blogs.msdn.com/b/adonet/archive/2007/01/26/querying-datasets-introduction-to-linq-to-dataset.aspx so perhaps I'll be able to figure this out using LINQ.