What is a View and how can it be used for aggregation?

An AMPS View is a special topic that is a user-defined projection of another topic. AMPS Views allow aggregation and real-time computation much like SQL-92 Views (where topics are tables.) The best part of a View topic is that it behaves just like any other State-of-the-World topic within AMPS supporting queries, subscriptions with content filters, and even advanced Out-of-Focus (OOF) processing.