**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))



query_plan.getCurrentDataStream(),
                        expressions.join,
                        settings.max_block_size);
                    filled_join_step->setStepDescription("JOIN");
                    query_plan.addStep(std::move(filled_join_step));
                }
                else
                {
                    auto joined_plan = query_analyzer->getJoinedPlan();
                    if (!joined_plan)
                        throw Exception(ErrorCodes::LOGICAL_ERROR, "There is no joined plan for query");
                    QueryPlanStepPtr join_step = std::make_unique<JoinStep>(
                        query_plan.getCurrentDataStream(),
                        joined_plan->getCurrentDataStream(),
                        expressions.join,
                        settings.max_block_size);
                    join_step->setStepDescription("JOIN");
                    std::vector<QueryPlanPtr> plans;
                    plans.emplace_back(std::make_unique<QueryPlan>(std::move(query_plan)));
                    plans.emplace_back(std::move(joined_plan));
                    query_plan = QueryPlan();
                    query_plan.unitePlans(std::move(join_step), {std::move(plans)});
                }
            }
            if (!query_info.projection && expressions.hasWhere())
                executeWhere(query_plan, expressions.before_where, expressions.remove_where_filter);
            if (expressions.need_aggregate)
            {
                executeAggregation(
                    query_plan, expressions.before_aggregation, aggregate_overflow_row, aggregate_final, query_info.input_order_info);