Re: pgsql aggregate: conditional max - Mailing list pgsql-sql

From Weimao Ke
Subject Re: pgsql aggregate: conditional max
Date
Msg-id 44145569.3010208@indiana.edu
Whole thread Raw
In response to Re: pgsql aggregate: conditional max  (Michael Fuhr <mike@fuhr.org>)
Responses Re: pgsql aggregate: conditional max
List pgsql-sql
Michael Fuhr wrote:

>SELECT DISTINCT ON (aid) aid, cat
>FROM tablename
>ORDER BY aid, weight DESC, cat;
>  
>
Good pointer. I think this will solve my problem. :)

>SELECT aid, cat
>FROM tablename AS t
>JOIN (SELECT aid, max(weight) AS weight
>      FROM tablename
>      GROUP BY aid) AS s USING (aid, weight);
>  
>
This query will return duplicates if there are multiple categories (for 
one aid) with the same max weight. Yet, I should be able to remove the 
duplicates somehow...:)

I really appreciate your help!

-- 
All best, 

Weimao

Weimao Ke
Indiana University Bloomington
School of Library and Information Science
http://ella.slis.indiana.edu/~wke



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