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

From: "Massa, Harald Armin" <chef(at)ghum(dot)de>
To: pgsql-general(at)postgresql(dot)org
Subject: Re: using window-functions to get freshest value - how?
Date: 2009-11-20 10:31:04
Message-ID: e3e180dc0911200231v3ef9eea0p61dd9640c66fae51@mail.gmail.com
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id_bf, wert, letztespeicherung:

> 98, 'blue', 2009-11-09
>> 98, 'red', 2009-11-10
>> now I have a select to get the "youngest value" for every id_bf:
>>
>
> Not tested:
>
> SELECT id_bf, wert,
> max(letztespeicherung) over (partition by id_bf)
> FROM rfmitzeit
>

no, that does not work:
"id_bf";"wert";"max"
98;"blue";"2009-11-10 00:00:00"
98;"red";"2009-11-10 00:00:00"

result is: I get the date of the youngest value.

My expected result is:

98;"red"

(that is, the entry of "wert" that is youngest)

thanks for trying,

Harald

--
GHUM Harald Massa
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Harald Armin Massa
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70435 Stuttgart
0173/9409607
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%s is too gigantic of an industry to bend to the whims of reality

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