Github user wuchong commented on a diff in the pull request: https://github.com/apache/flink/pull/3063#discussion_r95308316 --- Diff: flink-libraries/flink-table/src/main/scala/org/apache/flink/table/plan/logical/operators.scala --- @@ -92,20 +92,19 @@ case class Project(projectList: Seq[NamedExpression], child: LogicalNode) extend } override protected[logical] def construct(relBuilder: RelBuilder): RelBuilder = { - val allAlias = projectList.forall(_.isInstanceOf[Alias]) child.construct(relBuilder) - if (allAlias) { - // Calcite's RelBuilder does not translate identity projects even if they rename fields. - // Add a projection ourselves (will be automatically removed by translation rules). - val project = LogicalProject.create(relBuilder.peek(), + // Calcite's RelBuilder does not translate identity projects even if they rename fields. + // We add a projection ourselves (will be automatically removed by translation rules). + val project = LogicalProject.create( --- End diff -- Good point ! The hack code existed because of Calcite's RelBuilder does not create project when only rename fields. The `project( Iterable<? extends RexNode> nodes, Iterable<String> fieldNames, boolean force)` was introduced and fixed this issue by Calcite-1342. I have tried to replace the hack code by the following code, and all tests passed ! ```scala override protected[logical] def construct(relBuilder: RelBuilder): RelBuilder = { child.construct(relBuilder) relBuilder.project( projectList.map { case Alias(c, _, _) => c.toRexNode(relBuilder) case n@_ => n.toRexNode(relBuilder) }.asJava, projectList.map(_.name).asJava, true) } ```
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