**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))



expressions.prewhere_info->prewhere_actions->projectInput(false);
                expressions.prewhere_info->remove_prewhere_column = expressions.filter_info->do_remove_column;
                expressions.prewhere_info->need_filter = true;
                expressions.filter_info = nullptr;
            }
        }
        else
        {
            
            expressions.prewhere_info->row_level_filter = std::move(expressions.filter_info->actions);
            expressions.prewhere_info->row_level_column_name = std::move(expressions.filter_info->column_name);
            expressions.prewhere_info->row_level_filter->projectInput(false);
            expressions.filter_info = nullptr;
        }
    }
    auto & prewhere_info = analysis_result.prewhere_info;
    auto & columns_to_remove_after_prewhere = analysis_result.columns_to_remove_after_prewhere;
    
    auto alias_columns_required = false;
    const ColumnsDescription & storage_columns = metadata_snapshot->getColumns();
    for (const auto & column_name : required_columns)
    {
        auto column_default = storage_columns.getDefault(column_name);
        if (column_default && column_default->kind == ColumnDefaultKind::Alias)
        {
            alias_columns_required = true;
            break;
        }
    }