I have a map with a compound key which naturally sorts in an ascending
order as:
[No, 2011]
[No, 2012]
[Yes, 2011]
[Yes, 2012]

But I want it to sort as:
[No, 2012]
[No, 2011]
[Yes, 2012]
[Yes, 2011]

Which means the first element in the key No/Yes should be sorted in an
ascending order, whereas the timestamp should be sorted in a descending
order.

Is there a way to do this in a query? Or do I have to come up with some
hack in my mapping function?