Re: Debugging postmaster to fix possible bug in Postgres? Followup to "How do you select

Ooops! Appologies to all for being sooo stupid!

I thought the order by was applied before the WHERE and if ordering in DESC
order for example < would mean greater than and so on in the where clause
because I assumed < meant it would appear before in the returned order.

Of course the where just selects which values and the order by orders them!

Don't know how I even got confused in the first place. So there's no bug in
POstgres and I just wasted a day being dumb (guess I should get more than 2
hours sleep before tackling this kinda stuff!).

Thanks all,

On Thursday 13 Feb 2003 8:39 pm, Manfred Koizar wrote:
> On Thu, 13 Feb 2003 18:28:50 +0100, Nicholas Allen
>
> <nallen(at)freenet(dot)co(dot)uk> wrote:
> >Because the WHERE clause is directly affected by the ORDER BY clause.
>
> No, it's not (at least in your query).
>
> > If you
> >leave out the order by clause then the row count will be completely
> > different and therefore wrong.
>
> I must be missing something. Please give an example.
>
> > The ORDER BY clause is just as important as the WHERE
> >clause when counting rows. It should be possible to get a count for the
> > rows for any query that can be done which can return row data as I
> > understand it.
>
> If you have a set of numbers, say {1, 9, 5, 3, 7}, and want to know
> how many elements of the set are <= 7 (SELECT COUNT(*) FROM s WHERE
> n<=7), you simply look a each element - no matter in what order - and
> increase your counter, if the element satifies your condition. I
> can't see how you get different numbers when you count {1, 3, 5, 7},
> {1, 5, 3, 7} or any other permutation.
>
> >I have tried to find a definition for SQL SELECT command but everywhere I
> > have looked so far makes no mention of this being invalid SQL syntax. Can
> > you let me know where you got this information?
>
> SQL92 says:
> <direct select statement: multiple rows> ::=
> <query expression> [ <order by clause> ]
> [...]
> 3) Let T be the table specified by the <query expression>.
>
> 4) If ORDER BY is specified, then each <sort specification> in the
> <order by clause> shall identify a column of T.
>
> Servus
> Manfred