private Operator<?> createDummyScan() throws SemanticException {
    Table metadata = hiveOpConverter.getSemanticAnalyzer().getDummyTable();
    TableScanDesc tsd = new TableScanDesc(SemanticAnalyzer.DUMMY_TABLE, Collections.emptyList(), metadata);

    return OperatorFactory.get(
            hiveOpConverter.getSemanticAnalyzer().getOpContext(), tsd, new RowSchema(Collections.emptyList()));
  }
Converts empty {@link HiveValues} to a plan like
TS [DUMMY] - SEL [null, ..., null] - LIM [0]
ql/src/java/org/apache/hadoop/hive/ql/optimizer/calcite/translator/opconventer/HiveValuesVisitor.java