
```
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))
```
{
    switch (type)
    {
        case ActionType::INPUT:
            return "Input";
        case ActionType::COLUMN:
            return "Column";
        case ActionType::ALIAS:
            return "Alias";
        case ActionType::ARRAY_JOIN:
            return "ArrayJoin";
        case ActionType::FUNCTION:
            return "Function";
    }
    __builtin_unreachable();
}
void ActionsDAG::Node::toTree(JSONBuilder::JSONMap & map) const