Re: Aggregates

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От Richard Huxton
Тема Re: Aggregates
Дата
Msg-id 467A7B82.9030305@archonet.com
обсуждение исходный текст
Ответ на Aggregates  (Naz Gassiep <naz@mira.net>)
Ответы Re: Aggregates  ("John D. Burger" <john@mitre.org>)
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Naz Gassiep wrote:
> Hi,
>     If I have a table with users and a table with messages, is it
> possible to have a query that returns user.* as well as one extra column
> with the number of messages they have posted and the data and time of
> the last message? At the moment I am using a subquery to do this,
> however it seems suboptimal. Is there a better way?

Not really. You have three separate queries really:
1. User details
2. Total number of messages posted
3. Details on last message posted

Unless you have a messaging-summary table that you keep up-to-date with
triggers you're looking at a three-part query.
--
   Richard Huxton
   Archonet Ltd

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