Unknown identifier in aggregate function error when using same alias in different levels of query

[siradjev]

When same alias names are used in different levels of query in some cases "unknown identifier" errors are received.

Does it reproduce on recent release?
Yes, reproduces on all builds 21.3, 21.8, latest 21.9 too.

How to reproduce

chserver :) SELECT
:-]     sum(q0.a2) AS a1,
:-]     sum(q0.a1) AS a9
:-] FROM
:-] (
:-]     SELECT
:-]         1 AS a1,
:-]         2 AS a2
:-] ) AS q0
:-] ;

SELECT
    sum(q0.a2) AS a1,
    sum(q0.a1) AS a9
FROM
(
    SELECT
        1 AS a1,
        2 AS a2
) AS q0

Query id: cd2ff574-fcb3-4027-8fee-7a105bccde53


Received exception from server (version 21.8.5):
Code: 47. DB::Exception: Received from chserver:9000. DB::Exception: Unknown identifier 'a1' in aggregate function 'sum(a1) AS a9'.

0 rows in set. Elapsed: 0.121 sec.

chserver :) SELECT
:-]     (q0.a2) AS a1,
:-]     (q0.a1) AS a9
:-] FROM
:-] (
:-]     SELECT
:-]         1 AS a1,
:-]         2 AS a2
:-] ) AS q0
:-] ;

SELECT
    q0.a2 AS a1,
    q0.a1 AS a9
FROM
(
    SELECT
        1 AS a1,
        2 AS a2
) AS q0

Query id: ec6a030a-d8e2-4ad1-b7de-35bb74831ba6

┌─a1─┬─a9─┐
│  2 │  1 │
└────┴────┘

1 rows in set. Elapsed: 0.121 sec.

chserver :)

Expected behavior
It should work disregarding of order of columns in query.

[alexey-milovidov]

Hold until #23194 is implemented.