Re: BUG #19418: SQL/JSON JSON_VALUE() does not conform to ISO/IEC 9075-2:2023(E) 6.34 <JSON value constructor>

Lukas Eder <lukas.eder@gmail.com>

From: Lukas Eder <lukas.eder@gmail.com>
To: jian he <jian.universality@gmail.com>
Cc: Vik Fearing <vik@postgresfriends.org>, pgsql-bugs@lists.postgresql.org, PG Bug reporting form <noreply@postgresql.org>
Date: 2026-03-03T07:16:49Z
Lists: pgsql-bugs
That was a typo. I meant to refer to JSON_ARRAY, not JSON_VALUE in the
subject title. The issue is specifically about <JSON array constructor by
query> (I also made a typo there, sorry for that)

On Tue, Mar 3, 2026 at 3:42 AM jian he <jian.universality@gmail.com> wrote:

> On Thu, Feb 26, 2026 at 10:20 PM Vik Fearing <vik@postgresfriends.org>
> wrote:
> >
> > > Try this:
> > >
> > >    select json_array(select 1 where false);
> > >
> > > It produces NULL, not []
> >
> >
> > I can confirm that postgres violates the standard here.
> >
> > --
>
> Since the subject title mentioned JSON_VALUE.
>
> SELECT JSON_VALUE(((select NULL where false)), '$');
> SELECT JSON_QUERY(((select NULL where false)), '$');
> SELECT JSON_EXISTS(((select NULL where false)), '$');
>
> Should the above produce []?
>
>
>
> --
> jian
> https://www.enterprisedb.com/
>

Commits

  1. Enforce RETURNING typmod for empty-set JSON_ARRAY(query)

  2. Fix JSON_ARRAY(query) empty set handling and view deparsing