gmane.comp.python.sqlobject

Frank Wagner | 6 Apr 14:31

Re: select only one column, not the whole record

Sorry forgot something in my former post. See below

On Sun, Apr 6, 2008 at 2:29 PM, Frank Wagner <frank.wagner <at> nofusion.de> wrote:

Hi Daniel,

it will not be possible to achieve this with the regular SQLObject-classes. All you can do is something like this:

Yoursqlobject._connection.queryAll("select distinct ...") # hardcoded sql

or, to maintain more flexibility:

conn = Yoursqlobject._connection
conn.queryAll(conn.sqlrepr(Select(items=Yoursqlobject.q.column)))

this won´t include DISTINCT in the sql. this will:

results = conn.queryAll(conn.sqlrepr(Select(items=Yoursqlobject.q.column, distinct=True)))

HTH.

KR,
Frank

On Sun, Apr 6, 2008 at 7:55 AM, Daniel Fetchinson <fetchinson <at> googlemail.com> wrote:
Hi folks,

Is it possible to select only 1 column out of a table and not the
whole record? More specifically, what I really need is the following:

SELECT DISTINCT column FROM table;

The point is that I only need DISTINCT values and if I can't select 1
column only then I can't use DISTINCT because generally full records
are never the same but the value in 'column' might be repeated. So I
would need to select everything and filter through the data in python
which would be a huge performance hit.

Cheers,
Daniel

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Daniel Fetchinson | 6 Apr 18:59

Re: select only one column, not the whole record

> > it will not be possible to achieve this with the regular
> > SQLObject-classes. All you can do is something like this:
> >
> > Yoursqlobject._connection.queryAll("select distinct ...") # hardcoded sql
> >
> > or, to maintain more flexibility:
> >
> > conn = Yoursqlobject._connection
> > conn.queryAll(conn.sqlrepr(Select(items=Yoursqlobject.q.column)))
>
> this won´t include DISTINCT in the sql. this will:
>
> results = conn.queryAll(conn.sqlrepr(Select(items=Yoursqlobject.q.column,
> distinct=True)))

Hi Frank, the hard coded query of course works but I'd like to have
something go through sqlobject. The Select( ) actually does the trick
of selecting only 1 column, thanks! But it does not accept 'distinct'
as a keyword argument, I wonder why.

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Oleg Broytmann | 6 Apr 19:04

Re: select only one column, not the whole record

On Sun, Apr 06, 2008 at 09:59:56AM -0700, Daniel Fetchinson wrote:
> But it does not accept 'distinct'
> as a keyword argument, I wonder why.

   It does in SQLObject 0.10.0.

Oleg.
--

-- 
     Oleg Broytmann            http://phd.pp.ru/            phd <at> phd.pp.ru
           Programmers don't die, they just GOSUB without RETURN.

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Daniel Fetchinson | 6 Apr 19:14

Re: select only one column, not the whole record

> > But it does not accept 'distinct'
> > as a keyword argument, I wonder why.
>
>    It does in SQLObject 0.10.0.

Indeed! That's great, thanks a lot!

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