Re: [HACKERS] SELECT DISTINCT question

From: Hannu Krosing <hannu(at)trust(dot)ee>
To: Oleg Bartunov <oleg(at)sai(dot)msu(dot)su>
Cc: hackers(at)postgreSQL(dot)org, pgsql-sql(at)postgreSQL(dot)org
Subject: Re: [HACKERS] SELECT DISTINCT question
Date: 1999-07-13 20:50:57
Message-ID: 378BA6B1.2B226DDB@trust.ee
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers pgsql-sql

Oleg Bartunov wrote:
>
> I got a problem with query:
>
> select distinct (date), bytes from access_log;
>
> which works but not as I expect. I thought this query will select
> all rows with distinct values of 'date' column, but it get
> distinct pairs 'date, bytes' . From documnetation I see
>
> "DISTINCT will eliminate all duplicate rows from the selection.
> DISTINCT ON column will eliminate all duplicates in the specified column;
> this is equivalent to using GROUP BY column.

If it is equivalent to GROUP BY then it should allow only aggregates
in non-distinct columns, like:

select distinct on date date, sum(bytes) from access_log;

If it does not, then it should be files as a bug imho.

-----------------
Hannu

In response to

Browse pgsql-hackers by date

  From Date Subject
Next Message Tom Lane 1999-07-13 21:31:48 Re: [HACKERS] SELECT DISTINCT question
Previous Message Tom Lane 1999-07-13 19:26:22 Re: [HACKERS] PostgreSQL v6.5 - Tagged

Browse pgsql-sql by date

  From Date Subject
Next Message Tom Lane 1999-07-13 21:31:48 Re: [HACKERS] SELECT DISTINCT question
Previous Message Bruce Momjian 1999-07-13 17:00:02 Re: [SQL] Postgres ERROR