[jira] [Commented] (FLINK-18782) Retain the column name when converting a Table to a DataStream

["Atri Sharma (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/FLINK-18782?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17185041#comment-17185041 ] 

Atri Sharma commented on FLINK-18782:
-------------------------------------

[~ykt836] I am taking a crack at this – can you please suggest where can I start looking?

> Retain the column name when converting a Table to a DataStream
> --------------------------------------------------------------
>
>                 Key: FLINK-18782
>                 URL: https://issues.apache.org/jira/browse/FLINK-18782
>             Project: Flink
>          Issue Type: Sub-task
>          Components: Table SQL / Planner
>    Affects Versions: 1.9.1
>            Reporter: Ying Z
>            Priority: Major
>
> mail: [http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/How-to-retain-the-column-name-when-convert-a-Table-to-DataStream-td37002.html]
>  
> I met some field name errors when try to convert in Table and DataStream.
>  First, init a datastream and convert to table 'source', register a tablefunction named 'foo'
> {code:java}
> val sourceStream = env.socketTextStream("127.0.0.1", 8010)
>   .map(line => line.toInt)
> tableEnv.registerDataStream("source_table", sourceStream, 'a)
> class Foo() extends TableFunction[(Int)] {
>   def eval(col: Int): Unit = collect((col * 10))
> }
> tableEnv.registerFunction("foo", new Foo)
> {code}
> Then, use sqlQuery to generate a new table t1 with columns 'a' 'b'
> {code:java}
> val t1 = tableEnv.sqlQuery(
>   """
>     |SELECT source_table.a, b FROM source_table
>     |, LATERAL TABLE(foo(a)) as T(b)
>     |""".stripMargin
> )
> /*
>  t1 table schema: root
>  |-- a: INT
>  |-- b: INT
>  */
> println(s"t1 table schema: ${t1.getSchema}")
> {code}
> When I try to convert 't1' to a datastream then register to a new table(for some reason) named 't1', the columns changes to 'a' 'f0', not 'a' 'b'
> {code:java}
> val t1Stream = t1.toAppendStream[Row]
> // t1 stream schema: Row(a: Integer, f0: Integer)
> println(s"t1 stream schema: ${t1Stream.getType()}")
> tableEnv.registerDataStream("t1", t1Stream)
> /*
> new t1 table schema: root
> |-- a: INT
> |-- f0: INT
>  */
> println(s"new t1 table schema: ${tableEnv.scan("t1").getSchema}")
> {code}



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