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  1. Calcite
  2. CALCITE-3226

RelBuilder doesn't keep the alias when scan from an expanded view

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      Description

      In current implementation of RelBuilder::scan (https://github.com/apache/calcite/blob/master/core/src/main/java/org/apache/calcite/tools/RelBuilder.java#L1048), the alias can be derived and recorded into Frame only when the RelNode is a TableScan (https://github.com/apache/calcite/blob/master/core/src/main/java/org/apache/calcite/tools/RelBuilder.java#L2754).
      But when RelBuilder::scan from an expanded view, the node is not a TableScan and the alias is not kept.  Below test failed - we cannot reference a field by alias "MYVIEW".

        @Test public void testExpandViewShouldKeepAlias() throws SQLException {
          try (Connection connection = DriverManager.getConnection("jdbc:calcite:")) {
            final Frameworks.ConfigBuilder configBuilder =
                expandingConfig(connection);
            final RelOptTable.ViewExpander viewExpander =
                (RelOptTable.ViewExpander) Frameworks.getPlanner(configBuilder.build());
            final RelFactories.TableScanFactory tableScanFactory =
                RelFactories.expandingScanFactory(viewExpander,
                    RelFactories.DEFAULT_TABLE_SCAN_FACTORY);
            configBuilder.context(Contexts.of(tableScanFactory));
            final RelBuilder builder = RelBuilder.create(configBuilder.build());
            RelNode node =
                builder.scan("MYVIEW")
                    .project(
                        builder.field(1, "MYVIEW", "EMPNO"),           // Exception thrown from here.
                        builder.field(1, "MYVIEW", "ENAME"))
                    .build();
            String expected =
                "LogicalProject(EMPNO=[$0], ENAME=[$1])\n"
                    + "  LogicalFilter(condition=[=(1, 1)])\n"
                        + "    LogicalTableScan(table=[[scott, EMP]])\n";
            assertThat(node, hasTree(expected));
          }
        }
      

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              • Assignee:
                jinxing6042@126.com jin xing
                Reporter:
                jinxing6042@126.com jin xing
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                  Updated:
                  Resolved:

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