Received: from malur.postgresql.org ([217.196.149.56])
	by arkaria.postgresql.org with esmtps  (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
	(Exim 4.94.2)
	(envelope-from <pgsql-general-owner+archive@lists.postgresql.org>)
	id 1tD2yH-00FQfS-7H
	for pgsql-general@arkaria.postgresql.org; Mon, 18 Nov 2024 14:43:21 +0000
Received: from localhost ([127.0.0.1] helo=malur.postgresql.org)
	by malur.postgresql.org with esmtp (Exim 4.94.2)
	(envelope-from <pgsql-general-owner+archive@lists.postgresql.org>)
	id 1tD2yE-005M3G-IJ
	for pgsql-general@arkaria.postgresql.org; Mon, 18 Nov 2024 14:43:19 +0000
Received: from makus.postgresql.org ([2001:4800:3e1:1::229])
	by malur.postgresql.org with esmtps  (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
	(Exim 4.94.2)
	(envelope-from <dakkar@thenautilus.net>)
	id 1tD2yE-005M37-1S
	for pgsql-general@lists.postgresql.org; Mon, 18 Nov 2024 14:43:18 +0000
Received: from mail.thenautilus.net ([178.162.154.203])
	by makus.postgresql.org with esmtps  (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
	(Exim 4.94.2)
	(envelope-from <dakkar@thenautilus.net>)
	id 1tD2yB-002X21-Bn
	for pgsql-general@lists.postgresql.org; Mon, 18 Nov 2024 14:43:17 +0000
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed; d=thenautilus.net; h=date
	:from:to:subject:message-id:in-reply-to:references:mime-version
	:content-type:content-transfer-encoding; s=20240114; bh=tgorJkO6
	HBP9lh1BPhEysX6YUsauw9qEbIGrHP5n2+U=; b=QNHYzBCf6iPjt3PALqCr5Mua
	KzvUs7aWhWGtUG6rMAgemB3XqnOW9jNkbRxQCrCT0BkV+zI9XUdR54FjBFVANoen
	mcwDlbUQ4v6VJL3eLy/4zdpsDqlgJH3Zpng9Di5dbca347SYT/jSl2NBq2A1+R8S
	Hvk/wSdjQAgmkyyA3SXV4+t2rvcJ3iay2zCU/I0Q4gMTtPcbpeQfIYTprfEj7zCX
	RaC1aWJvVu9jr6pRXaD7VfVz/7khIV216GprJ5toDd8MANImuFx1TjLhbQlVI3Nf
	3NHGZKIqluzHvSox6RJfLM4Rjh9T5BvcwPsuIko4+g5nTabxXUEiEHCDXLOHhQ==
Received: (qmail 19850 invoked from network); 18 Nov 2024 14:43:12 -0000
Received: from unknown (HELO exelion) (dakkar@2001:1af8:4700:a096:2:8000::1006)
  by 0 with ESMTPA; 18 Nov 2024 14:43:12 -0000
Date: Mon, 18 Nov 2024 14:43:07 +0000
From: Gianni Ceccarelli <dakkar@thenautilus.net>
To: pgsql-general@lists.postgresql.org
Subject: Re: Functions and Indexes
Message-ID: <20241118144307.2017e712@exelion>
In-Reply-To: <8dfd0bd5-87e5-4de7-9f60-8a680a32bc11@evolu-s.it>
References: <2e36a2fe-b30f-46a5-937f-3b7d94e75cb6@evolu-s.it>
	<8dfd0bd5-87e5-4de7-9f60-8a680a32bc11@evolu-s.it>
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
List-Id: <pgsql-general.lists.postgresql.org>
List-Help: <https://lists.postgresql.org/manage/>
List-Subscribe: <https://lists.postgresql.org/manage/>
List-Post: <mailto:pgsql-general@lists.postgresql.org>
List-Owner: <mailto:pgsql-general-owner@lists.postgresql.org>
List-Archive: <https://www.postgresql.org/list/pgsql-general>
Archived-At: <https://www.postgresql.org/message-id/20241118144307.2017e712%40exelion>
Precedence: bulk

On Mon, 18 Nov 2024 15:37:57 +0100
Moreno Andreo <moreno.andreo@evolu-s.it> wrote:

> If a column appears in the WHERE clause (and so it should be placed
> in index), in case it is "processed" in a function (see below), is it 
> possible to insert this function to further narrow down things?

You probably want to look at
https://www.postgresql.org/docs/current/indexes-expressional.html

-- 
	Dakkar - <Mobilis in mobile>
	GPG public key fingerprint = A071 E618 DD2C 5901 9574
	                             6FE2 40EA 9883 7519 3F88
	                    key id = 0x75193F88