From: PG Doc comments form <noreply@postgresql.org>
To: pgsql-docs@lists.postgresql.org
Cc: estanislao.gonzalez@projo.zone
Subject: documentation extension request - order with function over aggregated functions
Date: Tue, 04 Feb 2020 08:59:41 +0000
Message-ID: <158080678185.1098.6542165890616974586@wrigleys.postgresql.org> (raw)
The following documentation comment has been logged on the website:
Page: https://www.postgresql.org/docs/9.5/queries-order.html
Description:
In https://www.postgresql.org/docs/9.5/queries-order.html it is said that
the following is intentionally not allowed:
```
SELECT a + b AS sum, c FROM table1 ORDER BY sum + c; -- wrong
```
It took me a while to figure out how to do it properly so I propose to add
the following (or similar) info:
---
If you need to sort by this kind of expression, you will have to retrieve an
extra column with the required computation and use it as a sorting key:
```
SELECT a + b AS sum, c FROM table1, a + b + c AS my sorting_key ORDER BY
my_sorting_key; -- correct
```
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Subject: Re: documentation extension request - order with function over aggregated functions
In-Reply-To: <158080678185.1098.6542165890616974586@wrigleys.postgresql.org>
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