MongoDB 2.1 introduced the aggregation framework, a faster alternative to
Map/Reduce for common aggregation operations. If you took a look at the
documentation and examples, you may have found the feature intimidating.
Once you tame it, this new feature reveals itself as a very powerful beast.
So read on to discover its true power through a series of examples.
Original title and link: Comparing MongoDB New Aggregation Framework and SQL ( ©myNoSQL)