Re: [ADMIN] Major upgrade advice

Why not simply,
SELECT * FROM xxx WHERE <timestamp_column>::date = '2008-05-20'::date;

Στις Thursday 19 June 2008 21:56:09 ο/η Roberto Garcia έγραψε:
> We changed it because 8.3 doesn't allow the operator LIKE on timestamp
> columns. Your syntax works fine but we weren't used to use as u do.
> There weren't any specific reason, only another way to do that.
>
> I think when we read that operator LIKE and timestamp values were
> incompatible we assumed that timestamp values couldn't be compared to
> any char value, opposed as your syntax is.
>
> We've tried to do "select * from X where <timestamp column> =
> '2008-05-20 10:'", expecting that the result would be any minute from 10
> o'clock (10:15, 10:30, 10:45, etc) of the specific date, but this syntax
> retrieves only 10:00 from that date.
>
> Tks for the new syntax.
>
> Regards
> Roberto Garcia
>
> Gregory S. Youngblood wrote:
> > That's a pretty substantial change. Why did you have to make this change?
> > Was it causing syntax errors or to get better performance on those types of
> > queries? Actually, now that I think about it, didn't:
> > select * from X where <timestamp column> between '2008-05-20 00:00:00' and
> > '2008-05-20 23:59:59'
> > work? I could have sworn I have used that syntax in 8.2 without having to
> > arbitrarily cast the arguments... now I'm going to have to go look. :)
> >
> > Yup, confirmed, 8.2.7 and no casting on the date arguments when I was using
> > between.
> >
> > I'm just curious if there was a specific reason (i.e. better performance,
> > better use of indexes, etc.) for your syntax.
> >
> > Thanks,
> > Greg
> >
> > -----Original Message-----
> > From: pgsql-admin-owner@postgresql.org
> > [mailto:pgsql-admin-owner@postgresql.org] On Behalf Of Roberto Garcia
> > Sent: Wednesday, June 18, 2008 12:01 PM
> > Cc: pgsql-admin@postgresql.org
> > Subject: Re: [ADMIN] Major upgrade advice
> >
> > Just to mention one issue we had here:
> >
> > In 8.1 we did this to retrieve all data from a specific date:
> > SELECT * FROM xxx
> > WHERE <timestamp_column> LIKE '2008-05-20%'
> >
> > In 8.3 we had to change to:
> > SELECT * FROM xxx
> > WHERE <timestamp_column> >= CAST('2008-05-20' as timestamp) AND
> > <timestamp_column> < CAST('2008-05-21' as timestamp)
> >
> > Regards
> > Roberto Garcia
> >
> >
> >
>
>
> Roberto Garcia
> Banco de Dados, MSc
> Fone: (12) 3186-8405
> --
> A luta contra o aquecimento global depende de cada um de nós, faça sua parte, economize recursos naturais.
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> http://www.inpe.br

>
>

--
Achilleas Mantzios

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