What is Spark SQL?

SQL has been the defacto language for business analysts for over two decades now. With the evolution and rise of big data came a new way of building business applications - APIs. However, people writing Map-Reduce soon realized that while Map-Reduce is an extremely powerful paradigm, it has limited reach due to the complex programming paradigm, and was akin to sidelining the business analysts who would previously use SQL to solve their business problems. The business analysts are people who have deep business knowledge, but limited knowledge around building applications through APIs and hence it was a huge ask to have them code their business problems in the new and shiny frameworks that promised a lot. This led the open source community to develop projects such as Hive and Impala, which made working with big data easier.

Similarly in the case of Spark, while RDDs are the most powerful APIs, they are perhaps too low level for business users. Spark SQL comes to the...