[jira] [Commented] (FLINK-5256) Extend DataSetSingleRowJoin to support Left and Right joins

["ASF GitHub Bot (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/FLINK-5256?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15855638#comment-15855638 ] 

ASF GitHub Bot commented on FLINK-5256:
---------------------------------------

Github user ex00 commented on a diff in the pull request:

    https://github.com/apache/flink/pull/3033#discussion_r99778650
  
    --- Diff: flink-libraries/flink-table/src/main/scala/org/apache/flink/table/plan/nodes/dataset/DataSetSingleRowJoin.scala ---
    @@ -144,21 +150,46 @@ class DataSetSingleRowJoin(
     
         val condition = codeGenerator.generateExpression(joinCondition)
     
    -    val joinMethodBody = s"""
    -                  |${condition.code}
    -                  |if (${condition.resultTerm}) {
    -                  |  ${conversion.code}
    -                  |  ${codeGenerator.collectorTerm}.collect(${conversion.resultTerm});
    -                  |}
    -                  |""".stripMargin
    +    val joinMethodBody =
    +      if (joinType == JoinRelType.INNER) {
    +        s"""
    +         |${condition.code}
    +         |if (${condition.resultTerm}) {
    +         |  ${conversion.code}
    +         |  ${codeGenerator.collectorTerm}.collect(${conversion.resultTerm});
    +         |}
    +         |""".stripMargin
    +    } else {
    +        val singleNode =
    +          if (leftIsSingle) {
    +            leftNode
    +          }
    +          else {
    +            rightNode
    +          }
    +        val notSuitedToCondition = singleNode
    +          .getRowType
    +          .getFieldList
    +          .map(field => getRowType.getFieldNames.indexOf(field.getName))
    +          .map(i => s"${conversion.resultTerm}.setField($i,null);")
    --- End diff --
    
    Hi @fhueske,
    Could you explain that we need generate in ```generateFieldAccesses(boolean firstInput)``` and in ```generateNullValues(boolean firstInput)``` from your coment? What is different between they and ```generateFieldAccess( inputType: TypeInformation[_], inputTerm: String, index: Int, pojoFieldMapping: Option[Array[Int]])``` and 
    ```generateNullLiteral(resultType: TypeInformation[_])``` from ```CodeGenerator``` ?


> Extend DataSetSingleRowJoin to support Left and Right joins
> -----------------------------------------------------------
>
>                 Key: FLINK-5256
>                 URL: https://issues.apache.org/jira/browse/FLINK-5256
>             Project: Flink
>          Issue Type: Improvement
>          Components: Table API & SQL
>    Affects Versions: 1.2.0
>            Reporter: Fabian Hueske
>            Assignee: Anton Mushin
>
> The {{DataSetSingleRowJoin}} is a broadcast-map join that supports arbitrary inner joins where one input is a single row.
> I found that Calcite translates certain subqueries into non-equi left and right joins with single input. These cases can be handled if the  {{DataSetSingleRowJoin}} is extended to support outer joins on the non-single-row input, i.e., left joins if the right side is single input and vice versa.



--
This message was sent by Atlassian JIRA
(v6.3.15#6346)