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