From: Bruce Momjian <bruce@momjian.us>
To: Peter Eisentraut <peter.eisentraut@enterprisedb.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Michael Paquier <michael@paquier.xyz>
Cc: Stephen Frost <sfrost@snowman.net>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>
Subject: Re: SELECT INTO deprecation
Date: Tue, 15 Dec 2020 17:13:25 -0500
Message-ID: <20201215221325.GA14807@momjian.us> (raw)
In-Reply-To: <737048bf-de51-3fd4-bbcc-89f6d2bd2c4f@enterprisedb.com>
References: <96dc0df3-e13a-a85d-d045-d6e2c85218da@enterprisedb.com>
<20201202175836.GX16415@tamriel.snowman.net>
<1672926.1606941346@sss.pgh.pa.us>
<X8gpP9GL7R5AsF3E@paquier.xyz>
<8e05fc79-abca-dd3f-4d48-8aaae9525a8f@enterprisedb.com>
<1723856.1607009655@sss.pgh.pa.us>
<a71c0215-3ab1-abab-babe-2778b17aa1d7@enterprisedb.com>
<737048bf-de51-3fd4-bbcc-89f6d2bd2c4f@enterprisedb.com>
On Wed, Dec 9, 2020 at 09:48:54PM +0100, Peter Eisentraut wrote:
> On 2020-12-03 20:26, Peter Eisentraut wrote:
> > On 2020-12-03 16:34, Tom Lane wrote:
> > > As I recall, a whole lot of the pain we have with INTO has to do
> > > with the semantics we've chosen for INTO in a set-operation nest.
> > > We think you can write something like
> > >
> > > SELECT ... INTO foo FROM ... UNION SELECT ... FROM ...
> > >
> > > but we insist on the INTO being in the first component SELECT.
> > > I'd like to know exactly how much of that messiness is shared
> > > by SQL Server.
> >
> > On sqlfiddle.com, this works:
> >
> > select a into t3 from t1 union select a from t2;
> >
> > but this gets an error:
> >
> > select a from t1 union select a into t4 from t2;
> >
> > SELECT INTO must be the first query in a statement containing a UNION,
> > INTERSECT or EXCEPT operator.
>
> So, with that in mind, here is an alternative proposal that points out that
> SELECT INTO has some use for compatibility.
Do we really want to carry around confusing syntax for compatibility? I
doubt we would ever add INTO now, even for compatibility.
--
Bruce Momjian <bruce@momjian.us> https://momjian.us
EnterpriseDB https://enterprisedb.com
The usefulness of a cup is in its emptiness, Bruce Lee
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To: pgsql-hackers@postgresql.org
Cc: bruce@momjian.us, peter.eisentraut@enterprisedb.com, tgl@sss.pgh.pa.us, michael@paquier.xyz, sfrost@snowman.net
Subject: Re: SELECT INTO deprecation
In-Reply-To: <20201215221325.GA14807@momjian.us>
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