D select unnamed_subquery1.* FROM (SELECT 42 a, 43 b);
┌───────┬───────┐
│   a   │   b   │
│ int32 │ int32 │
├───────┼───────┤
│    42 │    43 │
└───────┴───────┘

-- now it is 7
D select unnamed_subquery7.* FROM (FROM (SELECT 42 a, 43 b) t);
┌───────┬───────┐
│   a   │   b   │
│ int32 │ int32 │
├───────┼───────┤
│    42 │    43 │
└───────┴───────┘
-- now it is 8
D select unnamed_subquery8.* FROM (SELECT 84) t, (SELECT 42 a, 43 b);
┌───────┬───────┐
│   a   │   b   │
│ int32 │ int32 │
├───────┼───────┤
│    42 │    43 │
└───────┴───────┘

select unnamed_subquery1.* FROM (SELECT 42 a, 43 b);
┌───────┬───────┐
│   a   │   b   │
│ int32 │ int32 │
├───────┼───────┤
│    42 │    43 │
└───────┴───────┘

D select (select unnamed_subquery1.* FROM (SELECT 42 a, 43 b));
-- Error: Binder Error: Referenced table "unnamed_subquery1" not found!
-- Candidate tables: "unnamed_subquery8"

-- standard case, single unnamed subquery, the table is called "unnamed_subquery"
D select unnamed_subquery.* FROM (SELECT 42 a, 43 b);
┌───────┬───────┐
│   a   │   b   │
│ int32 │ int32 │
├───────┼───────┤
│    42 │    43 │
└───────┴───────┘
-- two unnamed subqueries, the second one is called "unnamed_subquery2"
D select unnamed_subquery.a, unnamed_subquery2.b FROM (SELECT 42 a), (SELECT 43 b);
┌───────┬───────┐
│   a   │   b   │
│ int32 │ int32 │
├───────┼───────┤
│    42 │    43 │
└───────┴───────┘
-- unnamed subqueries/subqueries WITHIN do not affect naming at the current level
D select unnamed_subquery.a, unnamed_subquery2.b FROM (FROM (SELECT 42 a) t), (SELECT 43 b);
┌───────┬───────┐
│   a   │   b   │
│ int32 │ int32 │
├───────┼───────┤
│    42 │    43 │
└───────┴───────┘
-- similarly names are stable and queries are portable
D select (select unnamed_subquery.a from (select 42 a, 43 b)) AS res;
┌───────┐
│  res  │
│ int32 │
├───────┤
│    42 │
└───────┘