Re: Filling null values - Mailing list pgsql-general

From Vincent Veyron
Subject Re: Filling null values
Date
Msg-id 1312645369.3492.121.camel@asus-1001PX.home
Whole thread Raw
In response to Filling null values  (jeffrey <johjeffrey@hotmail.com>)
List pgsql-general
Le vendredi 05 août 2011 à 09:32 -0700, jeffrey a écrit :
> I have a table that looks like this:
>
> homeid    city          date     measurement      pre/post
> 123   san francisco  1/2/2003     1458             pre
> 123   san francisco  NULL          1932             post
> 124   los angeles    2/4/2005      938               pre
> 124   NULL            NULL           266               pre
> 124   los angeles    7/4/2006      777               post
>
> I'd like to write a query so that I get the following result:
>
> homeid    city          date     measurement      pre/post
> 123   san francisco  1/2/2003     1458             pre
> 123   san francisco  1/2/2003      1932            post
> 124   los angeles    2/4/2005      938               pre
> 124   los angeles    2/4/2005       266              pre
> 124   los angeles    7/4/2006      777               post
>
> If a city or date is null, then it will fill from other not null
> values with the same homeid.  If given the choice, it will
> preferentially fill from a row where homeid AND pre/post match.  But
> if that doesn't match, then it will still fill from the same homeid.
>
> Does anyone have ideas for this?
>

If it's possible for you to export the data to a text file, it is very
easy to write a small Perl script that will replace NULLs by the
appropriate values.


--
Vincent Veyron
http://marica.fr/
Logiciel de gestion des sinistres et des contentieux pour le service juridique


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