Re: sorting and grouping with min/max

Поиск
Список
Период
Сортировка
От Andreas Kretschmer
Тема Re: sorting and grouping with min/max
Дата
Msg-id 20090301130849.GA9599@tux
обсуждение исходный текст
Ответ на Re: sorting and grouping with min/max  (Valentin Gjorgjioski <tinodj@mt.net.mk>)
Ответы Re: sorting and grouping with min/max
Список pgsql-novice
Valentin Gjorgjioski <tinodj@mt.net.mk> wrote:
>> i'm looking for a query that returns one row for each player with the
>> smallest cmd_nr value. after several hours i figured out the following
>> query
>>
>> SELECT * FROM command_queue GROUP BY id, params, player, cmd_nr, date
>> HAVING (player, cmd_nr) IN (SELECT player, MIN(cmd_nr) FROM
>> command_queue GROUP BY player)
>
> well... for sure it would be simpler if you say
>
> SELECT * FROM command_queue where
> (player, cmd_nr) IN (SELECT player, MIN(cmd_nr) FROM command_queue GROUP
> BY player)
>
> But, can be even simpler? I hate subqueries...

Maybe it is faster with an JOIN instead the IN(...), other solution:
wait for 8.4 windowing functions...


Andreas
--
Really, I'm not out to destroy Microsoft. That will just be a completely
unintentional side effect.                              (Linus Torvalds)
"If I was god, I would recompile penguin with --enable-fly."   (unknown)
Kaufbach, Saxony, Germany, Europe.              N 51.05082°, E 13.56889°

В списке pgsql-novice по дате отправления:

Предыдущее
От: Valentin Gjorgjioski
Дата:
Сообщение: Re: sorting and grouping with min/max
Следующее
От: Valentin Gjorgjioski
Дата:
Сообщение: Re: sorting and grouping with min/max