Empty arrays in parameterized views

[dkarelov]

Cannot pass empty arrays to parameterized views in an obvious way:

CREATE OR REPLACE VIEW test.pview AS SELECT {a:Array(Int32)} = []

SELECT * FROM test.pview(a=[])
produces error:
Code: 456. DB::Exception: Substitution a is not set. (UNKNOWN_QUERY_PARAMETER) (version 23.10.4.25 (official build))

BUT this works as expected:
SELECT * FROM test.pview(a='[]')

[den-crane]

Clickhouse is unable to deduce a type of an empty array. You need to use explicit cast []::Array(Int32)

CREATE OR REPLACE VIEW  pview 
  AS  SELECT {a:Array(Int32)} = []::Array(Int32);

SELECT * FROM  pview(a=[]::Array(Int32))

https://fiddle.clickhouse.com/4940c9a2-3d46-4fcb-b98b-545d2e9ec3ec

23.10 is out of support.

[dkarelov]

Thanks, it is clear that the issue is with casting - the point is: this is very unobvious and difficult to fix.
Should either be reflected in the docs or implicitly tried to be type-casted to the expected type.

Understood re support - will use fiddle next time, thanks.

[den-crane]

You can leave it open. It can be improved.