How to write fast Flink SQL
出处：
www.ververica.com
作者：
Godfrey He
Flink SQL is the most widely used relational API based on standard SQL. It provides unified batch processing and stream processing, which makes it easy to develop applications, and is already widely used for various use cases. Unlike the DataStream API, which offers the primitives of stream processing in a relatively low-level imperative programming API, the Flink SQL API offers a relatively high-level declarative API. This means that a program written with the DataStream API will transform
