examples/java/sql/README.md

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# Example Pipelines for Beam SQL and Schema Transforms

The examples included in this module serve to demonstrate the basic
functionality of Apache Beam SQL, and act as starting points for
the development of more complex pipelines.

## SQL transform

An example that leverage the powerful SQL syntax in Beam [SqlTransform](https://beam.apache.org/releases/javadoc/current/org/apache/beam/sdk/extensions/sql/SqlTransform.html) directly in your Beam pipelines.


[`SqlTransformExample`](https://github.com/apache/beam/blob/master/examples/java/sql/src/main/java/org/apache/beam/examples/sql/SqlTransformExample.java) is a simple pipeline that calculates multiple metrics per key : Min, Max and Sum.


## Schema transform

[Beam Schemas](https://beam.apache.org/documentation/programming-guide/#schemas) offer a flexible way of writing in code the same operations that are so easy to express in SQL.

[`SchemaTransformExample`](https://github.com/apache/beam/blob/master/examples/java/sql/src/main/java/org/apache/beam/examples/sql/SchemaTransformExample.java) is a simple pipeline that calculates multiple metrics per key : Min, Max and Sum.

## Running Examples

See [Apache Beam WordCount Example](https://beam.apache.org/get-started/wordcount-example/) for information on running these examples.

Gradle cmd line can be similar to:

`./gradlew clean :examples:java:sql:execute  --args="--runner=DirectRunner" -Pdirect-runner -PmainClass=org.apache.beam.examples.sql.SqlTransformExample`

## Beyond SQL and Schemas

Both SQL and Schema Transforms leverage Row type.
The same results can be achieved directly using Beam transforms on a KV input PCollection. See [Composed Cobiners example](https://github.com/apache/beam/blob/master/examples/java/src/main/java/org/apache/beam/examples/CoCombineTransformExample.java).