Re: I need a SQL...

When i run it, it works as intended (on pg 7.3.3). Which version do you use?

Are you absolutely sure you copied it exactly? You typed in '>=' and not '=', right?

/Mattias

----- Original Message -----
From: "Bjørn T Johansen" <btj(at)havleik(dot)no>
To: "Mattias Kregert" <mattias(at)kregert(dot)se>
Cc: <pgsql-general(at)postgresql(dot)org>
Sent: Thursday, September 11, 2003 3:02 PM
Subject: Re: [GENERAL] I need a SQL...

> Well, it's close... :)
>
> But it looks like the case doesn't work..
> If I run your sql, the timediff is negative.
>
> But if I run this:
> SELECT (stoptime-starttime+'24 hours') as timediff FROM mytable
> the timediff has correct value..
>
> Do you see any error in the case, cause I don't?
>
>
> BTJ
>
> On Thu, 2003-09-11 at 14:29, Mattias Kregert wrote:
> > Solution:
> >
> > SELECT starttime, stoptime, (CASE WHEN stoptime-starttime >= 0 THEN
> > stoptime-starttime ELSE stoptime-starttime+'24 hours' END) as timediff
> > FROM mytable;
> >
> > /Mattias
> >
> > ----- Original Message -----
> > From: Bjørn T Johansen
> > To: Andrew L. Gould
> > Cc: PostgreSQL general list
> > Sent: Thursday, September 11, 2003 2:12 PM
> > Subject: Re: [GENERAL] I need a SQL...
> >
> > On Thu, 2003-09-11 at 14:07, Andrew L. Gould wrote:
> > > On Thursday 11 September 2003 06:25 am, Bjørn T Johansen wrote:
> > > > I need to write a SQL that calculates the interval between a start time
> > > > and a stop time. This is the easy part. The problem is that I only have
> > > > the time part, i.e. no date, so how can I be sure to also calculate the
> > > > interval if the start time is before midnight and the stop time is after
> > > > midnight?
> > > >
> > > >
> > > > Regards,
> > > >
> > > > BTJ
> > >
> > > If the activity or period you are measuring can equal or exceed 12 hours, you
> > > won't be able to calculate it reliably without a start date and a stop date.
> > > If the periods are always less than 12 hours (and you assume all the data is
> > > good), then stop times that are less than start times would indicate an
> > > intervening midnight.
> > >
> > > The dates do not have to be in the same fields as the times, since you can add
> > > date and time data to create a timestamp for datetime calculations:
> > >
> > > (stop_date + stop_time) - (start_date + start_time)
> > >
> > > Best of luck,
> > >
> > > Andrew Gould
> >
> >
> >
> > Yes, the period can exceed 12 hours, so what you are saying is that this is not possible to solve
> > without the date part? I can write this logic in my business logic but I was hoping to
> > solve this in my database layer...
> >
> >
> > BTJ
>
>
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