Re: nicer examples for aggregate calls

On Wed, Aug 17, 2022 at 12:20:10PM -0400, Bruce Momjian wrote:
> On Sat, Oct 23, 2021 at 01:51:48PM +0000, PG Doc comments form wrote:
> > The following documentation comment has been logged on the website:
> >
> > Page: https://www.postgresql.org/docs/14/tutorial-agg.html
> > Description:
> >
> > currently, all of the examples are very simple, like
> >
> > SELECT city, max(temp_lo)
> > FROM weather
> > WHERE city LIKE 'S%' -- (1)
> > GROUP BY city
> > HAVING max(temp_lo) < 40;
> >
> > this example would be more complex and would allow users to search for
> > clause "filter":
> >
> > Finally, if we only care about cities whose names begin with “S” and we want
> > to calculate the number of observations in each city with temp_lo over 30,
> > we might do:
> >
> > SELECT city, max(temp_lo), count(*) filter (temp_lo>30),
> > FROM weather
> > WHERE city LIKE 'S%' -- (1)
> > GROUP BY city
> > HAVING max(temp_lo) < 40;
>
> Good idea. We didn't support FILTER at the time this query was added.
> Here is a patch which adds it.

Patch applied back to PG 10. Thanks.

--
Bruce Momjian <bruce(at)momjian(dot)us> https://momjian.us
EDB https://enterprisedb.com

Indecision is a decision. Inaction is an action. Mark Batterson