Re: How to select and result row number??

Tom Lane wrote:
> Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> writes:
> >>> select nextval('temp_counter'), * from (select .... order by ...);
> >>
> >> Approximately the same solution, but without saving the result in a temp
> >> table.
>
> > I thought about doing it this way. However, a subselect as a
> > pseudotable is not guaranteed to return the data in any specific order,
> > so I don't think this method work work reliably.
>
> Say what? Given the ORDER BY in the subselect, it will.
>
> Of course, you can't do any grouping or other processing at the outer
> level, but the example as given is just fine.

When you specify a table in FROM, there is no ordering to the table. Is
it guaranteed that a subquery in FROM _does_ have an ordering. Does
ANSI say it has an ordering? What if the subquery is involved in a
join?

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