@Override
        public RelNode visit(CatalogQueryOperation catalogTable) {
            ObjectIdentifier objectIdentifier = catalogTable.getTableIdentifier();
            return relBuilder.scan(
                    objectIdentifier.getCatalogName(),
                    objectIdentifier.getDatabaseName(),
                    objectIdentifier.getObjectName()
            ).build();
        }
Get the {@link AggCall} correspond to the aggregate or table aggregate expression.
core/src/main/java/org/apache/flink/table/planner/plan/QueryOperationConverter.java