
```
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))
```
{
    Node node;
    node.type = ActionType::INPUT;
    node.result_type = std::move(type);
    node.result_name = std::move(name);
    return addNode(std::move(node));
}
const ActionsDAG::Node & ActionsDAG::addInput(ColumnWithTypeAndName column)
{
    Node node;
    node.type = ActionType::INPUT;
    node.result_type = std::move(column.type);
    node.result_name = std::move(column.name);
    node.column = std::move(column.column);
    return addNode(std::move(node));
}
const ActionsDAG::Node & ActionsDAG::addColumn(ColumnWithTypeAndName column)
{
    if (!column.column)
        throw Exception(ErrorCodes::LOGICAL_ERROR, "Cannot add column {} because it is nullptr", column.name);
    Node node;
    node.type = ActionType::COLUMN;
    node.result_type = std::move(column.type);
    node.result_name = std::move(column.name);
    node.column = std::move(column.column);
    return addNode(std::move(node));
}
const ActionsDAG::Node & ActionsDAG::addAlias(const Node & child, std::string alias)