Re: using window-functions to get freshest value - how?

In response to Massa, Harald Armin :
> > > Is it possible? How would the SQL utilizing WINDOW-functions look like?
> >
> > there is no point in using window functions in here - simply use
> > "DISTINCT ON".
>
> and how would I use DISTINCT ON for this query? Please bear in mind,
> that there is more then one id_bf (just stopped the sample data with
> one of them)

For my example:

test=# select * from harald order by 1,2;
g | datum | value
---+------------+-------
1 | 2009-11-01 | 10
1 | 2009-11-02 | 11
1 | 2009-11-03 | 12
1 | 2009-11-05 | 1
2 | 2009-11-04 | 20
2 | 2009-11-10 | 100
(6 rows)

the solution with DISTINCT ON:

test=*# select distinct on (g) * from harald order by g, datum desc;
g | datum | value
---+------------+-------
1 | 2009-11-05 | 1
2 | 2009-11-10 | 100
(2 rows)

Regards, Andreas
--
Andreas Kretschmer
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