Content-Type: text/plain;
  charset="iso-8859-1"
From: Nicholas Allen <nallen@freenet.co.uk>
To: Dmitry Tkach <dmitry@openratings.com>
Subject: Re: How do you select from a table until a condition is met?
Date: Wed, 12 Feb 2003 20:10:15 +0100
User-Agent: KMail/1.4.1
References: <200302121910.38232.nallen@freenet.co.uk>
	<3E4AB0E7.3010101@openratings.com>
In-Reply-To: <3E4AB0E7.3010101@openratings.com>
Cc: pgsql-sql@postgresql.org
MIME-Version: 1.0
Content-Transfer-Encoding: quoted-printable
Message-Id: <200302122010.15297.nallen@freenet.co.uk>


Thanks, but I don't think thats what I want. Basically I need to get the ro=
w=20
offset of a record (ie row) in a result set returned from the database. I=
=20
know all the details of the row in question but when the search order chang=
es=20
I need to know the new index the row will have.=20

In other words, I was hoping I would be able to select upto a particular ro=
w=20
(not knowing its offset but knowing everything else about it) in a select=
=20
query.=20

Ideally I could do something like SELECT count(*) UNTIL col1=3Dvalue1 &&=20
col2=3Dval2 etc....

Of course there is no UNTIL in a select statement just a WHERE clause.

I know I didn't explain that very well!

Well I hope you can still help?
On Wednesday 12 Feb 2003 9:39 pm, Dmitry Tkach wrote:
> select * from table order by x limit 10; -- get first 10
> select * from table order by x offset 10 limit 10; -- get 10 - 20
> select * from table order by x offset 40 limit 10; -- get 40-50
>
> OR
>
> begin;
> declare mycursor cursor for select * from table order by x;
> fetch 10 from mycursor; -- get first 10
> fetch 10 from mycursor; -- get 10-20
> move 20 in mycursor;
> fetch 10 from mycursor; -- get 40-50
>
>
>
> Is that what you are talking about?
>
> Dima
>
> Nicholas Allen wrote:
> > Hi,
> >
> > I am hoping that someone can help me with a problem I have. I would like
> > to=3D be=3D20
> > able to perform a SELECT query to select values from a table upto a
> > certain=3D =3D20
> > row. The select may be ordered on a number of items. Is it possible to
> > do=3D =3D20
> > this and how should I do it?
> >
> > The reason I need this is because I have created a virtual table browser
> > cl=3D ass=3D20
> > that performs SQL queries to get the sections of the table the user is=
=3D20
> > interested in. This way I don't load the whole table onto the client
> > side. =3D If=3D20
> > the user changes the sort ordering I want to determine the row index th=
at
> > w=3D as=3D20
> > previously selected and scroll to that location.
> >
> > Any help would be very much appreciated.
> >
> > Thanks in advance,
> >
> > Nicholas Allen
> >
> > ---------------------------(end of broadcast)---------------------------
> > TIP 3: if posting/reading through Usenet, please send an appropriate
> > subscribe-nomail command to majordomo@postgresql.org so that your
> > message can get through to the mailing list cleanly