Received: from malur.postgresql.org ([217.196.149.56])
	by arkaria.postgresql.org with esmtps
 (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256)
	(Exim 4.92)
	(envelope-from <pgsql-docs-owner+archive@lists.postgresql.org>)
	id 1oALZt-000402-MP
	for pgsql-docs@arkaria.postgresql.org; Sun, 10 Jul 2022 01:17:41 +0000
Received: from localhost ([127.0.0.1] helo=malur.postgresql.org)
	by malur.postgresql.org with esmtp (Exim 4.92)
	(envelope-from <pgsql-docs-owner+archive@lists.postgresql.org>)
	id 1oALZs-0003Bg-Ft
	for pgsql-docs@arkaria.postgresql.org; Sun, 10 Jul 2022 01:17:40 +0000
Received: from magus.postgresql.org ([2a02:c0:301:0:ffff::29])
	by malur.postgresql.org with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256)
	(Exim 4.92)
	(envelope-from <bruce@momjian.us>)
	id 1oALZs-00039T-8r
	for pgsql-docs@lists.postgresql.org; Sun, 10 Jul 2022 01:17:40 +0000
Received: from momjian.us ([72.94.173.45])
	by magus.postgresql.org with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256)
	(Exim 4.92)
	(envelope-from <bruce@momjian.us>)
	id 1oALZp-000533-Q3
	for pgsql-docs@lists.postgresql.org; Sun, 10 Jul 2022 01:17:39 +0000
Received: from bruce by momjian.us with local (Exim 4.94.2)
	(envelope-from <bruce@momjian.us>)
	id 1oALZn-0019YI-W6; Sat, 09 Jul 2022 21:17:35 -0400
Date: Sat, 9 Jul 2022 21:17:35 -0400
From: Bruce Momjian <bruce@momjian.us>
To: adrian.nesse.wiik@gmail.com, pgsql-docs@lists.postgresql.org
Subject: Re: Section I - 2.9: Use SELECT to confirm set of rows before DELETE
Message-ID: <Ysoor4WiNJGmCAba@momjian.us>
References: <165455035739.573549.17628498892386696027@wrigleys.postgresql.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: 
 <165455035739.573549.17628498892386696027@wrigleys.postgresql.org>
List-Id: <pgsql-docs.lists.postgresql.org>
List-Help: <https://lists.postgresql.org/manage/>
List-Subscribe: <https://lists.postgresql.org/manage/>
List-Post: <mailto:pgsql-docs@lists.postgresql.org>
List-Owner: <mailto:pgsql-docs-owner@lists.postgresql.org>
List-Archive: <https://www.postgresql.org/list/pgsql-docs>
Archived-At: 
 <https://www.postgresql.org/message-id/Ysoor4WiNJGmCAba%40momjian.us>
Precedence: bulk

On Mon, Jun  6, 2022 at 09:19:17PM +0000, PG Doc comments form wrote:
> The following documentation comment has been logged on the website:
> 
> Page: https://www.postgresql.org/docs/14/tutorial-delete.html
> Description:
> 
> Since this tutorial section is coined at beginners, I think it could be
> useful to tip users about the possibility to use a SELECT statement with the
> exact same qualification(s) as the DELETE statement they're planning to run
> to see which rows are about to be deleted, to avoid unintended deletion of
> rows. I suggest something like this:
> 
> ...
> Without a qualification, DELETE will remove all rows from the given table,
> leaving it empty. The system will not request confirmation before doing
> this!
> 
> You can check which rows will be deleted by any DELETE statement on the
> form:
> ```DELETE FROM tablename ... <qualificaton> ...```
> by rewriting it into a corresponding SELECT statement:
> ```SELECT * FROM tablename ... <qualification> ...```
> 
> This is my first attempt at contributing to the community, so please be
> nice. :)

Uh, this is more of a general SQL training that we don't normally cover
in the Postgres docs --- we try to focus on Postgres-specific stuff that
people need to know.

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EDB                                      https://enterprisedb.com

  Indecision is a decision.  Inaction is an action.  Mark Batterson