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From: Lukas Eder <lukas.eder@gmail.com>
Date: Tue, 3 Mar 2026 08:16:49 +0100
Message-ID: <CAB4ELO7eg5O4+Z+Xt653FX9EDkyZzV-JO6ii73q9sK17gg9LpA@mail.gmail.com>
Subject: Re: BUG #19418: SQL/JSON JSON_VALUE() does not conform to ISO/IEC
 9075-2:2023(E) 6.34 <JSON value constructor>
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>
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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=E2=80=AFAM jian he <jian.universality@gmail.com=
> wrote:

> On Thu, Feb 26, 2026 at 10:20=E2=80=AFPM 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/
>

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<div dir=3D"ltr">That was a typo. I meant to refer to JSON_ARRAY, not JSON_=
VALUE in the subject title. The issue is specifically about=C2=A0&lt;JSON a=
rray constructor by query&gt; (I also made a typo there, sorry for that)</d=
iv><br><div class=3D"gmail_quote gmail_quote_container"><div dir=3D"ltr" cl=
ass=3D"gmail_attr">On Tue, Mar 3, 2026 at 3:42=E2=80=AFAM jian he &lt;<a hr=
ef=3D"mailto:jian.universality@gmail.com">jian.universality@gmail.com</a>&g=
t; wrote:<br></div><blockquote class=3D"gmail_quote" style=3D"margin:0px 0p=
x 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">On Thu=
, Feb 26, 2026 at 10:20=E2=80=AFPM Vik Fearing &lt;<a href=3D"mailto:vik@po=
stgresfriends.org" target=3D"_blank">vik@postgresfriends.org</a>&gt; wrote:=
<br>
&gt;<br>
&gt; &gt; Try this:<br>
&gt; &gt;<br>
&gt; &gt;=C2=A0 =C2=A0 select json_array(select 1 where false);<br>
&gt; &gt;<br>
&gt; &gt; It produces NULL, not []<br>
&gt;<br>
&gt;<br>
&gt; I can confirm that postgres violates the standard here.<br>
&gt;<br>
&gt; --<br>
<br>
Since the subject title mentioned JSON_VALUE.<br>
<br>
SELECT JSON_VALUE(((select NULL where false)), &#39;$&#39;);<br>
SELECT JSON_QUERY(((select NULL where false)), &#39;$&#39;);<br>
SELECT JSON_EXISTS(((select NULL where false)), &#39;$&#39;);<br>
<br>
Should the above produce []?<br>
<br>
<br>
<br>
--<br>
jian<br>
<a href=3D"https://www.enterprisedb.com/" rel=3D"noreferrer" target=3D"_bla=
nk">https://www.enterprisedb.com/</a><br>
</blockquote></div>

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