unable to use projection expr in later predicate

[universalmind303]

Description

MRE

> select null as v 
::: from './testdata/csv/userdata1.csv'
::: where v is not null;
Error: Schema error: No field named v. Valid fields are "./testdata/csv/userdata1.csv".registration_dttm, "./testdata/csv/userdata1.csv".id, "./testdata/csv/userdata1.csv".first_name, "./testdata/csv/userdata1.csv".last_name, "./testdata/csv/userdata1.csv".email, "./testdata/csv/userdata1.csv".gender, "./testdata/csv/userdata1.csv".ip_address, "./testdata/csv/userdata1.csv".cc, "./testdata/csv/userdata1.csv".country, "./testdata/csv/userdata1.csv".birthdate, "./testdata/csv/userdata1.csv".salary, "./testdata/csv/userdata1.csv".title, "./testdata/csv/userdata1.csv".comments.

Note: you can order by the expr, but not filter by it.

select 1 as v, * from './testdata/csv/userdata1.csv' order by v;

Additional Context.

This works as expected in duckdb and clickhouse.

[scsmithr]

fwiw this doesn't work in postgres

postgres=# select a as aa from (values (1), (2)) t1(a) where a = 1;
 aa 
----
  1
(1 row)

postgres=# select a as aa from (values (1), (2)) t1(a) where aa = 1;
ERROR:  column "aa" does not exist
LINE 1: select a as aa from (values (1), (2)) t1(a) where aa = 1;
                                                          ^
HINT:  Perhaps you meant to reference the column "t1.a".