Re: Update FROM clause?

Поиск
Список
Период
Сортировка
От Booth, Robert
Тема Re: Update FROM clause?
Дата
Msg-id 419D2EB7B461D411A53B00508B69181D06232954@sdex02.sd.intuit.com
обсуждение исходный текст
Ответ на Update FROM clause?  ("Booth, Robert" <Robert_Booth@intuit.com>)
Список pgsql-general
> "Booth, Robert" <Robert_Booth@intuit.com> writes:
> > SELECT count(*)
> >   FROM (allforms LEFT OUTER JOIN aanda ON allforms.file__no =
> > aanda.file__no)
> >  INNER JOIN formsin ON allforms.file__no = formsin.file__no
> >  WHERE ... Omitted ...
>
> > The Postgres UPDATE Query:
> > UPDATE allforms
> >    SET status = 'Okay to Edit'
> >   FROM formsin LEFT OUTER JOIN aanda ON formsin.file__no =
> aanda.file__no
> >  WHERE allforms.file__no = formsin.file__no
> >    AND ... Omitted, matches the Access Query ...
>
> Those are not the same thing at all.  Your UPDATE is more like
>
> SELECT ...
> FROM allforms,
>      (formsin LEFT OUTER JOIN aanda ON formsin.file__no =
> aanda.file__no)
> WHERE allforms.file__no = formsin.file__no
>   AND ... Omitted, matches the Access Query ...
>
> which is reversing the order of the inner and outer join steps.
> Depending on your data this might yield quite a different result.
>
>             regards, tom lane
>

I was thinking about that, but when I run the selects I end up with the same
records.  I've been checking them since I sent the email.  So I'm wondering
what I'm missing, or how I can get the UPDATE to perform the same as the
SELECT, that uses the same structure.

Rob


В списке pgsql-general по дате отправления:

Предыдущее
От: "Roderick A. Anderson"
Дата:
Сообщение: Re: [Q] Sequences, last_value and inserts
Следующее
От: Tom Lane
Дата:
Сообщение: Re: [Q] Sequences, last_value and inserts