layout: section title: “Beam SQL: Overview” section_menu: section-menu/sdks.html permalink: /documentation/dsls/sql/overview/
Beam SQL: Overview
Beam SQL allows a Beam user (currently only available in Beam Java) to query bounded and unbounded PCollections with SQL statements. Your SQL query is translated to a PTransform, an encapsulated segment of a Beam pipeline. You can freely mix SQL PTransforms and other PTransforms in your pipeline.
There are three main things you will need to know to use SQL in your pipeline:
- Apache Calcite: a widespread SQL dialect used in big data processing with some streaming enhancements. Calcite provides the basic dialect underlying Beam SQL. We have added additional extensions to make it easy to leverage Beam's unified batch/streaming model and support for complex data types.
- [SqlTransform]({{ site.baseurl }}/documentation/sdks/javadoc/{{ site.release_latest }}/index.html?org/apache/beam/sdk/extensions/sql/SqlTransform.html): the interface for creating
PTransforms from SQL queries. - [Row]({{ site.baseurl }}/documentation/sdks/javadoc/{{ site.release_latest }}/index.html?org/apache/beam/sdk/values/Row.html): the type of elements that Beam SQL operates on. A
PCollection<Row> plays the role of a table.
The [SQL pipeline walkthrough]({{ site.baseurl }}/documentation/dsls/sql/walkthrough) works through how you use these.