Re: Probably simple answer

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От Andrew Gould
Тема Re: Probably simple answer
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Msg-id 20011109010116.60146.qmail@web13404.mail.yahoo.com
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Ответ на Re: Probably simple answer  (Peter Eisentraut <peter_e@gmx.net>)
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Thanks.  Sometimes there's just no getting around a
little work.  :-)

Andrew Gould

--- Peter Eisentraut <peter_e@gmx.net> wrote:
> Andrew Gould writes:
>
> > I think he simply wants the rows of the result set
> > numbered from 1 to whatever the last row is.  This
> is
> > useful for referencing rows when discussing
> reports.
> > It is also an immense help when calculating a
> record's
> > statistical percentile ranking.
> >
> > Doing it in a table is no problem.  But how do you
> > create one dynamically in a select query?
>
> It's not easily possible.
>
> Even if you were to write a server-side function
> that would implement such
> a counter, there is no guarantee that the rows would
> be returned in the
> order that the function is called in.  (Depending on
> how you express the
> query it can be very likely, but there is no
> guarantee.)
>
> It gets worse if you use ORDER BY or DISTINCT.  Then
> the problem amounts
> to adding a column to the result set after sorting,
> which is not possible
> in the SQL query model.
>
> So by far the easiest choice is to keep this counter
> in the client
> application as you loop through the result set.
>
> --
> Peter Eisentraut   peter_e@gmx.net
>
>
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