From: Tom Lane <tgl@sss.pgh.pa.us>
To: Igor Korot <ikorot01@gmail.com>
cc: "David G. Johnston" <david.g.johnston@gmail.com>,
        Adrian Klaver <adrian.klaver@aklaver.com>,
        "pgsql-generallists.postgresql.org" <pgsql-general@lists.postgresql.org>
Subject: Re: Determine server version from psql script
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Comments: In-reply-to Igor Korot <ikorot01@gmail.com>
	message dated "Sat, 22 Mar 2025 21:28:14 -0500"
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Date: Sat, 22 Mar 2025 23:01:41 -0400
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Igor Korot <ikorot01@gmail.com> writes:
> On Sat, Mar 22, 2025, 8:58=E2=80=AFPM David G. Johnston <david.g.johnsto=
n@gmail.com>
> wrote:
>> Then read the psql docs.  Your version has \if and you=E2=80=99ll find =
server
>> version listed as the available client variables.

> I was hoping for something like

> If server_version >=3D X:
>      CREATE OR REPLACE TRIGGER...

psql's \if doesn't (yet) have any native expression evaluation
ability, so you have to farm out the ">=3D" comparison.  The
psql docs suggest relying on the server to do it, which would
go along the lines of

select current_setting('server_version_num')::int >=3D 130000 as v13
\gset
\if :v13
   ... do something
\else
   ... do something else
\endif

You could also do the comparison client-side, along the lines of

\set v13 `expr :SERVER_VERSION_NUM \>=3D 130000`
\if :v13
  ... etc

But that introduces assorted platform dependencies and requires
close attention to correct shell quoting, so it's seldom
preferable IMO.

			regards, tom lane