I am trying to populate more columns in the query below, could someone assist me?

QUERY:

var query = from r in SQLresults.AsEnumerable()
            group r by r.Field<string>("COLUMN_ONE") into groupedTable
            select new
            {
                 c1 = groupedTable.Key,
                 c2 = groupedTable.Sum(s => s.Field<decimal>("COLUMN_TWO")),                            
            };

How could I get a column named COLUMN_THREE in this query ?

Thanks in advance