Finding duplicate rows

There is no direct way which give you rows grouped by duplicate values. However, there are work arounds. For example, you can loop through a DataTable and get the value of first row and select all rows from the DataTable which matches with the value of the first row using DataTable.Select method. Now you should have all rows with matches and next take another unmatched row and call DataTable.Select again. I think this method would be better than going through each row.