**Describe what's wrong**

Query with rollup using same selected field name as the name of underlying column reports structure mismatch

**Does it reproduce on recent release?**

yes

**How to reproduce**

`21.9.2.17`

```sql
CREATE TABLE test
(
    `d` DateTime,
    `a` LowCardinality(String),
    `b` UInt64
)
ENGINE = MergeTree
PARTITION BY toDate(d)
ORDER BY d;

SELECT *
FROM (
    SELECT
        a,
        max((d, b)).2 AS value
    FROM test
    GROUP BY rollup(a)
)
WHERE a <> '';
```

**Expected behavior**

This used to return an ok result on v21.8

**Error message and/or stacktrace**

> Code: 352. DB::Exception: Block structure mismatch in (columns with identical name must have identical structure) stream: different columns:
> notEquals(a, '') LowCardinality(UInt8) ColumnLowCardinality(size = 0, UInt8(size = 0), ColumnUnique(size = 1, UInt8(size = 1)))
> notEquals(a, '') LowCardinality(UInt8) Const(size = 0, ColumnLowCardinality(size = 1, UInt8(size = 1), ColumnUnique(size = 2, UInt8(size = 2)))). (AMBIGUOUS_COLUMN_NAME) (version 21.9.2.17 (official build))



#pragma once
#include <Processors/ISimpleTransform.h>
#include <Common/Arena.h>
namespace DB
{
class Arena;
using ArenaPtr = std::shared_ptr<Arena>;
class ExpressionActions;
using ExpressionActionsPtr = std::shared_ptr<ExpressionActions>;
class ActionsDAG;
enum class TotalsMode;
/** Takes blocks after grouping, with non-finalized aggregate functions.
  * Calculates total values according to totals_mode.
  * If necessary, evaluates the expression from HAVING and filters rows. Returns the finalized and filtered blocks.
  */
class TotalsHavingTransform : public ISimpleTransform
{
public:
    TotalsHavingTransform(
        const Block & header,
        bool overflow_row_,
        const ExpressionActionsPtr & expression_,
        const std::string & filter_column_,
        TotalsMode totals_mode_,
        double auto_include_threshold_,
        bool final_);
    String getName() const override { return "TotalsHavingTransform"; }
    OutputPort & getTotalsPort() { return outputs.back(); }