
```
select *
from (
select 'table' as table, toInt64(10) as rows, toInt64(101) as elements
union all
select 'another table' as table, toInt64(0) as rows, toInt64(0) as elements
)
where rows - elements <> 0

DB::Exception: Block structure mismatch in Pipe::unitePipes stream: different number of columns:
table String String(size = 0), rows Int64 Int64(size = 0), elements Int64 Int64(size = 0)
table String String(size = 0), rows Int64 Int64(size = 0), elements Int64 Int64(size = 0), dummy UInt8 UInt8(size = 0) (version 21.5.3.1 (official build))
```
{
    for (auto & node : index)
        node = &materializeNode(*node);
}
const ActionsDAG::Node & ActionsDAG::materializeNode(const Node & node)
{
    FunctionOverloadResolverPtr func_builder_materialize = std::make_unique<FunctionToOverloadResolverAdaptor>(
                            std::make_shared<FunctionMaterialize>());
    const auto & name = node.result_name;
    const auto * func = &addFunction(func_builder_materialize, {&node}, {});
    return addAlias(*func, name);
}
ActionsDAGPtr ActionsDAG::makeConvertingActions(
    const ColumnsWithTypeAndName & source,
    const ColumnsWithTypeAndName & result,
    MatchColumnsMode mode,
    bool ignore_constant_values,
    bool add_casted_columns,
    NameToNameMap * new_names)
{
    size_t num_input_columns = source.size();
    size_t num_result_columns = result.size();
    if (mode == MatchColumnsMode::Position && num_input_columns != num_result_columns)
        throw Exception("Number of columns doesn't match", ErrorCodes::NUMBER_OF_COLUMNS_DOESNT_MATCH);
    if (add_casted_columns && mode != MatchColumnsMode::Name)
        throw Exception("Converting with add_casted_columns supported only for MatchColumnsMode::Name", ErrorCodes::LOGICAL_ERROR);
    auto actions_dag = std::make_shared<ActionsDAG>(source);