Re: SQL question: Highest column value of unique column pairs

Hello Kevin,

I would use "select distinct on" to first isolate the candidates in (1)
and (2) and then reitere the query on this sub result:
(the query below will retrieve the last score, not the best one...)

something like (not tested):

select distinct on (date,name)
date,name,score
from

(select distinct (on date, LName1)
date,LName1 as name ,score1 as score
from table
order by date desc,LName1

union all

select distinct on (date, LName2)
date,LName2 as name,score2 as score
from table
order by date desc, LName2
)foo

order by date desc,name

regards,

Marc Mamin

-----Original Message-----
From: pgsql-sql-owner(at)postgresql(dot)org
[mailto:pgsql-sql-owner(at)postgresql(dot)org] On Behalf Of Kevin Jenkins
Sent: Saturday, January 12, 2008 1:10 AM
To: pgsql-sql(at)postgresql(dot)org
Subject: [SQL] SQL question: Highest column value of unique column pairs

Hi,

I have the following table which holds the result of 1 on 1 matches:

FName1, LName1, Score1, FName2, LName2, Score2, Date
John, Doe, 85 Bill, Gates, 20 Jan 1.
John, Archer, 90 John, Doe, 120 Jan 5
Bob, Barker, 70 Calvin, Klien 8 Jan 8
John, Doe, 60 Bill, Gates, 25 Jan 3.

So columns 1 and 2 hold the first person. Column 3 holds his score.
Columns 4 and 5 hold the second person. Column 6 holds his score.

I want to return the most recent score for each person (be they an
opponent or myself). And the resultant table shouldn't care if they are
person 1 or 2.

So the end result would be

FName, LName, Score, Date
John, Doe, 120 Jan 5.
John, Archer 90 Jan 5.
Bob, Barker 70 Jan 8
Bill, Gates 25 Jan 3
Calvin Klien 8 Jan 8

Thanks for any help!

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