From: Tom Lane <tgl@sss.pgh.pa.us>
To: John Lumby <johnlumby@hotmail.com>
Cc: pgsql-docs@lists.postgresql.org <pgsql-docs@lists.postgresql.org>
Subject: Re: Set-Returning functions in a select list
Date: Tue, 27 Jul 2021 13:24:03 -0400
Message-ID: <351778.1627406643@sss.pgh.pa.us> (raw)
In-Reply-To: <DM5PR06MB3082924AB2D1A3135D23F9C1A3E99@DM5PR06MB3082.namprd06.prod.outlook.com>
References: <DM5PR06MB3082924AB2D1A3135D23F9C1A3E99@DM5PR06MB3082.namprd06.prod.outlook.com>
John Lumby <johnlumby@hotmail.com> writes:
> I feel that more on this topic needs to be added to the reference information for SELECT,
> both in the description of the (expressions in the) SELECT-list and in the description of the FROM list, and in particular a note on how and why certain usages are equivalent when written in specific ways, (and maybe even which is preferred).
> Currently there is a thorough description of the semantics of [ LATERAL ] ROWS FROM in the FROM list, but very little about the effect of placing one or more what set-returning functions in the SELECT-list. Also there should be a reference to the chapters under "Query Language (SQL) Functions" , especially sub-chapter "SQL Functions Returning Sets"
The bigger picture here is that there's a lot of detail in 38.5 that
is of interest to users of built-in functions, not only to people
writing new functions. We've had discussions before about refactoring
that material so that some of it could be moved into a more prominent
place, probably in chapter 7 (Queries) or maybe chapter 9 (Functions
and Operators). Nobody's produced a coherent proposal though. In the
meantime I'm not much on board with sprinkling cross-references into
random places, if only because those references will be pointing to
the wrong place when/if this refactoring does happen.
regards, tom lane
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-docs@postgresql.org
Cc: tgl@sss.pgh.pa.us, johnlumby@hotmail.com, pgsql-docs@lists.postgresql.org
Subject: Re: Set-Returning functions in a select list
In-Reply-To: <351778.1627406643@sss.pgh.pa.us>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox