@Override
  public PlanNode visitNode(StatementNode node, MPPQueryContext context) {
    throw new UnsupportedOperationException(
        "Unsupported statement type: " + node.getClass().getName());
  }
This visitor is used to generate a logical plan for the statement and returns the {@link
PlanNode}.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/planner/LogicalPlanVisitor.java