Re: How to just get the last in a recursive query

From: Shaozhong SHI <shishaozhong(at)gmail(dot)com>
To: Rob Sargent <robjsargent(at)gmail(dot)com>
Cc: "pgsql-sql(at)lists(dot)postgresql(dot)org" <pgsql-sql(at)lists(dot)postgresql(dot)org>
Subject: Re: How to just get the last in a recursive query
Date: 2022-04-04 23:21:52
Message-ID: CA+i5JwZR_XYcbU_bekoAo1rAE=6+X+je_7+4+repLztLZqxoHg@mail.gmail.com
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That is not the most efficient in this case.
How to tell query to deliberately miss out all except the last one is of
interest.
Regards, David

On Monday, 4 April 2022, Rob Sargent <robjsargent(at)gmail(dot)com> wrote:

> On 4/4/22 16:14, Shaozhong SHI wrote:
>
>
>
> ---------- Forwarded message ---------
> From: Shaozhong SHI <shishaozhong(at)gmail(dot)com>
> Date: Mon, 4 Apr 2022 at 23:13
> Subject: How to just get the last in a recursive query
> To: PostGIS Users Discussion <postgis-users(at)lists(dot)osgeo(dot)org>
>
>
> In this example, Network Walking in PostGIS · Paul Ramsey
> (cleverelephant.ca)
> <http://blog.cleverelephant.ca/2010/07/network-walking-in-postgis.html>
>
> 3 rows got returns as follows:
>
> id
> ---
> 6
> 3
> 1
>
> How to just get the last (namely, 1) in the most efficient way?
>
> Regards, David
>
> reverse the order of the last query and set limit 1
>

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