This should work:
SELECT day, rain FROM meteo WHERE rain = (SELECT max(rain) FROM meteo
WHERE date_part('year', day) = '2001')
Michael Fork - CCNA - MCP - A+
Network Support - Toledo Internet Access - Toledo Ohio
On Thu, 8 Mar 2001, Salvador [iso-8859-1] Mainé wrote:
> Hello:
>
> I have a table with pluviometrical data
>
> meteo (rain float, day date, oid station)
>
> I want to select the the day of maximum value for each year for a given
> measurement station. It should look like :
>
> select max(rain),day from meteo group by date_part('year', day) where
> station=7654765;
>
> though it obiously doesn't work.
>
> I think that an aggregate function would be the best way to do this,
> because the table is quite large and I need indexes for date and also
> for stations, so adding a new one for the rain is too much. But the
> aggregate should look like:
>
> max_rain(rain, day) and return the day corresponding to the maximum
> rain, So the query would be something like:
>
> select max(rain), max_rain(rain, day) from meteo group by
> date_part('year', day) where station=47654765;
>
> I've tried to define a composite type for rain and day and the neccesary
> functions to make the aggregate, but I cannot find the correct way. Can
> someone help me? Is this sollution possible?
>
> --
> Salvador Maine
> http://www.ronincoders.com
>
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