Re: Your question about date

Perhaps it will be better if you put an 'order by' in the select.

SELECT
(( select test1.date
from test test1
where test1.date > test.date order by date limit 1)
- test.date ) AS result from test order by date;

result
--------
42
31
33
25

Regards,
Beatrice

Am Dienstag, den 22.03.2005, 10:38 +0100 schrieb Christoph Haller:
> That's a good one, but it has the disadvantage of
> giving a null result row:
> insert into test values ( '2004-12-22' ) ;
> The SELECT from below gives
> result
> --------
> 31
> 33
> 25
> (null)
> 42
> (5 rows)
> Also, I am not sure about the order of values.
> Anyway, Béatrice, thanks for your time.
> Regards, Christoph
>
Am Montag, den 21.03.2005, 06:06 -0800 schrieb Octavio Alvarez Piza:
> YES! It definitely should work. You guys are good! I'll make it
> first thing to try after vacation. I think I will only need to
> add an ORDER BY test1.date ASC clause.
>
> Heh... This method could also work for getting next/last-record on
> serials...
>
> Octavio.
>
>
> Béatrice Yueksel wrote:
> >
> > Dear Christoph,
> > perhaps you could try something like this example.
> > Regards,
> > BĂŠatrice
> >
> > The table:
> > ----------
> > # select * from test;
> > date
> > ------------
> > 2005-02-02
> > 2005-03-05
> > 2005-04-07
> > 2005-05-02
> > (4 rows)
> >
> > The query
> > ----------
> >
> > SELECT
> > (( select test1.date
> > from test test1
> > where test1.date > test.date limit 1)
> > - test.date ) AS result from test;
> >
> > t1.date >
> > RESULT:
> > -------
> > result
> > --------
> > 31
> > 33
> > 25
> >
> > Am Montag, den 21.03.2005, 10:54 +0100 schrieb Christoph Haller:
> > > Octavio Alvarez wrote:
> > > >
> > > > Sorry, I tried to make my subject as good as possible.
> > >
> > > Ahem, what subject?
> > > >
> > > > I have a table where I store the dates in which I take out of my inventory
> > > > (like "installation dates")
> > > >
> > > > table
> > > > ---------------
> > > > row_id SERIAL
> > > > date DATE
> > > > fk_item INTEGER
> > > >
> > > > and that's pretty much it.
> > > >
> > > > I want to have a query returning how long have been certain items lasting.
> > > >
> > > > Say I have:
> > > >
> > > > SELCT date FROM table WHERE fk_item = "INKJET_INK-BW"
> > > >
> > > > date
> > > > -------------
> > > > 2005-02-02
> > > > 2005-03-05
> > > > 2005-04-07
> > > > 2005-05-02
> > > >
> > > > I need something to calculate the intervals between those dates, like this:
> > > >
> > > > intervals (in days)
> > > > --------------------
> > > > 31
> > > > 34
> > > > 25
> > > >
> > > > So I can get the stddev and stuff from the "duration" of the items.
> > > >
> > > > I've been having a hard time with it. I'm trying NOT to program new
> > > > functions.
> > >
> > > I cannot see how this could be achieved without the use of a function.
> > > But if there is a way after all, I would be interested in learning it.
> > > >
> > > > Any help will be appreciated.
> > > >
> > > > --Octavio
> > > > --
> > >
> > > Regards, Christoph
> > >
--
Béatrice Yueksel
Softwareentwicklung

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