var list =

from tx in Transactions

group tx by new {tx.TransactionType, tx.ClientTypeID};



foreach (var item in list)

{

  Console.WriteLine(item.Key.TransactionType);

  Console.WriteLine(item.Sum(tx => tx.Amount));

  foreach (var item2 in item)

    Console.WriteLine(item2.TransactionID);

}

After executing the query, we now have an IGrouping<AnonymousType, Transaction> that lets us run through all of the grouped objects, while still having access to the original objects in the inner loop. We can accomplish the exact same thing with this alternative LINQ statement, but the first version seems cleaner to me:

var list =

from tx in Transactions

group tx by new {tx.TransactionType, tx.ClientTypeID} into g

select g;