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https://issues.apache.org/jira/browse/FLINK-5256?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16003019#comment-16003019
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ASF GitHub Bot commented on FLINK-5256:
---------------------------------------
Github user fhueske commented on a diff in the pull request:
https://github.com/apache/flink/pull/3673#discussion_r115535989
--- Diff:
flink-libraries/flink-table/src/main/scala/org/apache/flink/table/runtime/MapJoinLeftRunner.scala
---
@@ -31,7 +32,19 @@ class MapJoinLeftRunner[IN1, IN2, OUT](
override def flatMap(multiInput: IN1, out: Collector[OUT]): Unit = {
broadcastSet match {
case Some(singleInput) => function.join(multiInput, singleInput, out)
- case None =>
+ case None => {
--- End diff --
Why not? We configure the `CodeGenerator` to expect `null` as input (see
`DataSetSingleRowJoin` line 134).
The generated code will make sure we do not run into a NPE an the generated
condition will be `false` if one of the input is `null`.
So, we can simply do `case None if outerJoin => function.join(multiInput,
null.asInstanceOf[IN2], out)` here and `case None if outerJoin =>
function.join(null.asInstanceOf[IN1], multiInput, out)` in `MapJoinRightRunner`.
I check the generated code and this seems to be fine. Also the tests that
you provided pass with that change.
> 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: Dmytro Shkvyra
>
> 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.
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