You have to provide the following information whenever possible.

**Describe the bug**
This query fails with the latest stable version 21.5.5.12. It worked with the last stable version 21.4.7.3.

**Does it reproduce on recent release?**
yes

**How to reproduce**
21.5.5.12

```
SELECT
    label,
    number
FROM
(
    SELECT
        'a' AS label,
        number
    FROM
    (
        SELECT number
        FROM numbers(10)
    )
    UNION ALL
    SELECT
        'b' AS label,
        number
    FROM
    (
        SELECT number
        FROM numbers(10)
    )
)
WHERE number IN
(
    SELECT number
    FROM numbers(5)
)
```

**Expected behavior**
Query should run without errors

**Error message and/or stacktrace**
```
Received exception from server (version 21.5.5):
Code: 49. DB::Exception: Received from localhost:9000. DB::Exception: Block structure mismatch in Pipe::unitePipes stream: different names of columns:
label String String(size = 0), number UInt64 UInt64(size = 0), 'b' String Const(size = 0, String(size = 1))
label String String(size = 0), number UInt64 UInt64(size = 0), 'a' String Const(size = 0, String(size = 1)).
```

}
        case ActionsDAG::ActionType::ARRAY_JOIN:
        {
            auto key = arguments.at(0);
            key.column = key.column->convertToFullColumnIfConst();
            const ColumnArray * array = typeid_cast<const ColumnArray *>(key.column.get());
            if (!array)
                throw Exception(ErrorCodes::TYPE_MISMATCH,
                                "ARRAY JOIN of not array: {}", node->result_name);
            res_column.column = array->getDataPtr()->cloneEmpty();
            break;
        }
        case ActionsDAG::ActionType::COLUMN:
        {
            res_column.column = node->column->cloneResized(0);
            break;
        }
        case ActionsDAG::ActionType::ALIAS:
        {
            res_column.column = arguments.at(0).column;
            break;
        }
        case ActionsDAG::ActionType::INPUT:
        {
            break;
        }
    }
    return res_column;
}
Block ActionsDAG::updateHeader(Block header) const