From: Weimao Ke <wke@indiana.edu>
To: pgsql-sql@postgresql.org
Subject: pgsql aggregate: conditional max
Date: Sun, 12 Mar 2006 00:09:48 -0500
Message-ID: <4413AD1C.9050604@indiana.edu> (raw)
Hi,
I need a special aggregation function. For instance, given the following
table data:
aid | cat | weight
----------+---------+---------
a1 | Drama | 1
a1 | Romance | 6
a1 | Short | 1
a1 | Other | 7
a2 | Comedy | 1
a2 | Drama | 2
a3 | Drama | 1
a3 | Adult | 2
a3 | Comedy | 1
a3 | Other | 1
I want to group by "aid" and choose the category (i.e., "cat") with the
largest "weight":
aid | max_weighted_cat
----+---------------------
a1 | Other
a2 | Drama
a3 | Adult
Any ideas? Thank you! :)
--
All best,
Weimao
Weimao Ke
Indiana University Bloomington
School of Library and Information Science
http://ella.slis.indiana.edu/~wke
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To: pgsql-sql@postgresql.org
Cc: wke@indiana.edu
Subject: Re: pgsql aggregate: conditional max
In-Reply-To: <4413AD1C.9050604@indiana.edu>
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