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: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Kevin Jenkins
Sent: Saturday, January 12, 2008 1:10 AM
To: pgsql-sql@postgresql.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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