Home > mailing lists

count distinct and group by - Mailing list pgsql-general

From	Szymon Guz
Subject	count distinct and group by
Date	May 7, 2015 13:24:09
Msg-id	CAFjNrYtrTMFmRVrz=PyWkm-SBQQq28DvTzmsaYuVP-bqjPERDQ@mail.gmail.com Whole thread Raw
Responses	Re: count distinct and group by Re: count distinct and group by Re: count distinct and group by
List	pgsql-general

Hi,

I'm not sure why there is a reason for such behaviour.

For this table:

create table bg(id serial primary key, t text);

This works:

select count(id) from bg;

This works:

select count(distinct id) from bg;

And this doesn't:

select count(distinct id) from bg order by id;

ERROR: column "bg.id" must appear in the GROUP BY clause or be used in an aggregate function

LINE 1: select count(distinct id) from bg order by id;

thanks,

Szymon

From: Tim Clarke
Date: 07 May 2015, 11:36:53
Subject: Re: detached query?

From: Magnus Hagander
Date: 07 May 2015, 13:39:07
Subject: Re: count distinct and group by