Github user fhueske commented on a diff in the pull request:
https://github.com/apache/flink/pull/3033#discussion_r96419377
--- 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 --
This only works if the result term is a `Row`.
It think a better approach is to generate a dedicated result expression for
the null case based on `CodeGenerator.generateResultExpression()`, where the
field expressions are the outer fields and the null expressions. Then we could
use the current result expression if the condition is met and the result
expression with null values if that is not the case.
We would need to extend the `CodeGenerator` with methods for
`generateFieldAccesses(boolean firstInput)` (see
`generateConverterResultExpression()`) and `generateNullValues(boolean
firstInput)` which generates expressions for null values.
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