Re: insert only if conditions are met?

Thanks for all your answers. Very helpful.
What if after adding all those hours in one long transaction,
I want to send a query to check the MONTHLY TOTAL HOURS
(including those just entered)
and if they exceed N number of hours, all those records added
should *ROLLBACK*?

BEGIN;
insert..........
insert.........
if sum(hours)>N then ROLLBACK
END;

Is that possible? Maybe with just plain SQL? (and one transaction)

On 8/31/05, Philip Hallstrom <postgresql(at)philip(dot)pjkh(dot)com> wrote:
>
> > On Wed, 2005-08-31 at 12:49 -0400, Henry Ortega wrote:
> >> Ok. Here's TABLE A
> >>
> >> emp date hours type
> >> JSMITH 08-15-2005 5 WORK
> >> JSMITH 08-15-2005 3 WORK
> >> JSMITH 08-25-2005 6 WORK
> >>
> >> I want to insert the ff:
> >> 1.) JSMITH 08-15-2005 8 VAC
> >> 2.) DOE 08-16-2005 8 VAC
> >>
> >> #1 should fail because there is already 8 hours entered as being
> >> Worked on 08-15-2005 (same date).
> >
> > sorry, did not notice the duplicates before my previous reply.
> >
> > you could do something like
> > insert into A select 'JSMITH','08-15-2005',8,'VAC'
> > where
> > 8 != (select sum(hours) FROM A
> > WHERE emp = 'JSMITH'
> > AND date = '8-15-2005');
>
> Wouldn't that fail if JSMITH had only worked 7 hours on 8-15? I'm
> guessing he'd still want it to fail since adding that 8 hours ov VAC would
> result in a 15 hour day... so maybe something like?
>
> insert into A select 'JSMITH','08-15-2005',8,'VAC'
> WHERE
> 8 >= 8 + (select sum(hours) FROM A
> WHERE emp = 'JSMITH'
> AND date = '8-15-2005');
>
> ?
>