Re: aggregates of aggregates

Поиск
Список
Период
Сортировка
От Tom Lane
Тема Re: aggregates of aggregates
Дата
Msg-id 7162.967435324@sss.pgh.pa.us
обсуждение исходный текст
Ответ на aggregates of aggregates  (Tor Roberts <pg@econsci.net>)
Список pgsql-general
Tor Roberts <pg@econsci.net> writes:
> Does anyone know of any plans to support aggregates of aggregates in the
> future?

Not directly: it makes no sense in the SQL semantic model.  We do have
plans to support subselect-in-FROM (hopefully in 7.2), which would allow
constructs like

SELECT count(*) FROM (SELECT foo,count(*) FROM bar GROUP BY foo)

The same revisions will also be needed before views that involve
grouping or aggregates will work right in all but the simplest cases.

> My solution was to put the result of the first aggregate function in a
> temp table, then doing the other select statement on the temp table. This
> is not very efficient as the temp table can have up to a million records
> in it.

Sounds like a good workaround for now.

            regards, tom lane

В списке pgsql-general по дате отправления:

Предыдущее
От: Louis Bertrand
Дата:
Сообщение: book publishing date?
Следующее
От: Tom Lane
Дата:
Сообщение: Re: bits & the end of the world