http://deprecated-apache-flink-user-mailing-list-archive.369.s1.nabble.com/SQL-flatten-or-quality-docs-location-tp12230p12239.html
Hi Stu,
there is only one page of documentation for the Table API and SQL [1].
I agree the structure could be improved and split into multiple pages.
Regarding the flatting of a Pojo have a look at the "Built-In Functions" section [2].
If you select "SQL" and head to the "Value access functions", you'll find
> tableName.compositeType.* : Converts a Flink composite type (such as Tuple, POJO, etc.)
and all of its direct subtypes into a flat representation where every
subtype is a separate field.
The following program works returns the correct result:
// POJO definition
class MyPojo(var x: Int, var y: Int) {
def this() = this(0, 0)
}
// SQL query
val env = ExecutionEnvironment.getExecutionEnvironment
val tEnv = TableEnvironment.getTableEnvironment(env, config)
val ds = env.fromElements((0, new MyPojo(1, 2)), (1, new MyPojo(2, 3)), (2, new MyPojo(3, 4)) )
tEnv.registerDataSet("Pojos", ds, 'id, 'pojo)
val result = tEnv.sql("SELECT id, Pojos.pojo.* FROM Pojos") // you need to include the table name to flatten a Pojo
val results = result.toDataSet[Row].collect()
println(results.mkString("\n"))
// Result
0,1,2
1,2,3
2,3,4
Best, Fabian
[1]
https://ci.apache.org/projects/flink/flink-docs-release-1.2/dev/table_api.html[2]
https://ci.apache.org/projects/flink/flink-docs-release-1.2/dev/table_api.html#built-in-functions