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
2017-03-15 21:31 GMT+01:00 Stu Smith <stu26c...@gmail.com>:
> The documentation seems to indicate that there is a flatten method
> available in the sql language interface (in the table of available
> methods), or, alternatively using the '*' character somehow (in the text
> above the table).
>
> Yet I cannot flatten a POJO type, nor can I find any sufficient
> documentation in the official docs, searching the mailing list via
> markmail, looking through the examples in the source, or looking for
> through the SQL tests in the source.
>
> Can someone point me to the correct location for some solid flink SQL
> examples and docs?
>
> Take care,
> -stu
>
