From: Chao Li <li.evan.chao@gmail.com>
Message-Id: <3AB5E620-D210-4061-A5F0-F0B453CF3F4D@gmail.com>
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Subject: Re: SQL:2023 JSON simplified accessor support
Date: Tue, 2 Sep 2025 13:27:29 +0800
In-Reply-To: 
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Cc: Alexandra Wang <alexandra.wang.oss@gmail.com>,
 Nikita Glukhov <glukhov.n.a@gmail.com>,
 jian he <jian.universality@gmail.com>,
 Nikita Malakhov <hukutoc@gmail.com>,
 Vik Fearing <vik@postgresfriends.org>,
 Mark Dilger <mark.dilger@enterprisedb.com>,
 Matheus Alcantara <matheusssilv97@gmail.com>,
 Peter Eisentraut <peter@eisentraut.org>,
 Andrew Dunstan <andrew@dunslane.net>,
 PostgreSQL Hackers <pgsql-hackers@postgresql.org>,
 "David E. Wheeler" <david@justatheory.com>
To: "David G. Johnston" <david.g.johnston@gmail.com>
References: <d2d872c3-84f9-48f6-9963-f4537f02bc91@eisentraut.org>
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> On Sep 2, 2025, at 11:53, David G. Johnston =
<david.g.johnston@gmail.com> wrote:
>=20
> On Monday, September 1, 2025, Chao Li <li.evan.chao@gmail.com =
<mailto:li.evan.chao@gmail.com>> wrote:
>>=20
>> The last comment is about error message:
>>=20
>> ```
>> evantest=3D# select data.a from test_jsonb_types;
>> ERROR:  missing FROM-clause entry for table "data"
>> LINE 1: select data.a from test_jsonb_types;
>> ```
>>=20
>> =E2=80=9CMissing FROM-clause entry=E2=80=9D is quite confusing and =
not providing much useful hint to resolve the problem. When I first saw =
this error, I was stuck. Only after read through the commit comments, I =
figured out the problem. For end users, we should provide some more =
meaningful error messages.
>>=20
>=20
> I don=E2=80=99t think it=E2=80=99s fair to blame this patch set for =
this.  If you want to reference a component of a composite column you =
need to write ([tbl.]col).field otherwise the parser gets confused =
because it wants the thing prior to =E2=80=9Cfield=E2=80=9D to be a =
table name if you don=E2=80=99t use the parentheses.  This comes up all =
the time if one uses composite typed columns.  I=E2=80=99ll agree this =
isn=E2=80=99t the greatest error message but I=E2=80=99d suggest =
starting a new thread if you want to see about improving it.
>=20
> David J.
>=20


Sure, we can discuss the topic separately.

--
Chao Li (Evan)
HighGo Software Co., Ltd.
https://www.highgo.com/


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<html><head><meta http-equiv=3D"content-type" content=3D"text/html; =
charset=3Dutf-8"></head><body style=3D"overflow-wrap: break-word; =
-webkit-nbsp-mode: space; line-break: after-white-space;"><br =
id=3D"lineBreakAtBeginningOfMessage"><div><br><blockquote =
type=3D"cite"><div>On Sep 2, 2025, at 11:53, David G. Johnston =
&lt;david.g.johnston@gmail.com&gt; wrote:</div><br =
class=3D"Apple-interchange-newline"><div>On Monday, September 1, 2025, =
Chao Li &lt;<a =
href=3D"mailto:li.evan.chao@gmail.com">li.evan.chao@gmail.com</a>&gt; =
wrote:<br><blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 =
.8ex;border-left:1px #ccc solid;padding-left:1ex"><div =
style=3D"line-break:after-white-space"><br><div>The last comment is =
about error =
message:</div><div><br></div><div>```</div><div><div>evantest=3D# select =
data.a from test_jsonb_types;</div><div>ERROR: &nbsp;missing FROM-clause =
entry for table "data"</div><div>LINE 1: select data.a from =
test_jsonb_types;</div></div><div>```</div><div><br></div><div>=E2=80=9CMi=
ssing FROM-clause entry=E2=80=9D is quite confusing and not providing =
much useful hint to resolve the problem. When I first saw this error, I =
was stuck. Only after read through the commit comments, I figured out =
the problem. For end users, we should provide some more meaningful error =
messages.</div><div><br></div></div></blockquote><div><br></div><div>I =
don=E2=80=99t think it=E2=80=99s fair to blame this patch set for =
this.&nbsp; If you want to reference a component of a composite column =
you need to write ([tbl.]col).field otherwise the parser gets confused =
because it wants the thing prior to =E2=80=9Cfield=E2=80=9D to be a =
table name if you don=E2=80=99t use the parentheses.&nbsp; This comes up =
all the time if one uses composite typed columns.&nbsp; I=E2=80=99ll =
agree this isn=E2=80=99t the greatest error message but I=E2=80=99d =
suggest starting a new thread if you want to see about improving =
it.</div><div><br></div><div>David J.</div><div><br></div>
</div></blockquote></div><div><br></div><div>Sure, we can discuss the =
topic separately.</div><br><div>
<div dir=3D"auto" style=3D"caret-color: rgb(0, 0, 0); color: rgb(0, 0, =
0); letter-spacing: normal; text-align: start; text-indent: 0px; =
text-transform: none; white-space: normal; word-spacing: 0px; =
-webkit-text-stroke-width: 0px; text-decoration: none; overflow-wrap: =
break-word; -webkit-nbsp-mode: space; line-break: =
after-white-space;"><div>--</div><div>Chao Li (Evan)<br>HighGo Software =
Co., Ltd.<br>https://www.highgo.com/</div><div><br></div></div><br =
class=3D"Apple-interchange-newline"><br =
class=3D"Apple-interchange-newline">

</div>
<br></body></html>=

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