NoSQL database systems are designed for scalability. The down side of that is a primitive key-value data model and, as the name suggest, no support for SQL. It might sound like a serious limitation – how can I “select”, “join”, “group” and “sort” the data? This post explains how all these operations can be quite naturally and efficiently implemented in one of the most famous NoSQL system – Cassandra.

Wow, great explanations of conversion from SQL to NoSQL thinking in here.