BUG: in SELECT DISTINCT

This may be a bug:

select distinct on location nlid,location,postedon,title from newsletter
order by postedon,location desc limit 12

does not actually return a list of entries that are ordered first by the
date they were posted, but distinct on the "location" variable.

The results of this select are as follows:

nlid|location | postedon|title
----+---------------+---------+---------------------------------------------
--
9|R-TIB |932065380|Network Launch
11|C-AFG |932067219|Status 1999
12|C-IND |932067351|The causes of persecution
15|C-NPL |932067538|Church Growing Rapidly in Nepal
17|C-CHN |932067641|New information & opportunities
18|C-ALB |932067684|New articles about Albania
19|C-ERI |932067769|Welcome to Eritrea!
20|C-RUS |932067821|Is Russia Y2K ready?
24|P-2021 |932069031|Welcome to the Uighur
25|P-1675 |932069111|Welcome to the Nara
26|P-1704 |932069160|Welcome to the Afar!
33|F-2 |932498871|WELCOME TO THE NORTH AMERICAN CCMN FORUM
PAGE!
42|F-4 |933013973|<B>A MILLENNIAL TRIBUTE TO JESUS (Issue
#1)</B>
43|C-IND |933017367|Conditions for 300 Million Indian Children
44|R-TIB |933017654|Macao - the City of God or the City of Sin?

Note that R-TIB occurrs both at the top & at the bottom, because the
"location" column is not the first in the order grouping. But, if you do it
this way:

select distinct on location nlid,location,postedon,title from newsletter
order by location,postedon desc limit 12

Thenw hat I get is this:

nlid|location | postedon|title
----+---------------+-------------------------------------------------------
------------------------------------------
150|A- |936895571|Straight Line - #06
163|C-AFG |937321006|9/13 UN lashes Taliban over poor human rights
record
18|C-ALB |932067684|New articles about Albania
122|C-BTN |936018559|Dzalakha of Bhutan Untargeted from Joshua
Project 2000 List
17|C-CHN |932067641|New information & opportunities
63|C-CUB |933174509|Cuban Evangelical Celebration
19|C-ERI |932067769|Welcome to Eritrea!
13|C-IND |932067399|Can "Hindutva" survive the persecution of
Christians in India?
113|C-IRN |935081148|Welcome 8/19/99
80|C-MNG |933536089|Number of Believers Growing Rapidly in
Mongolia
15|C-NPL |932067538|Church Growing Rapidly in Nepal
20|C-RUS |932067821|Is Russia Y2K ready?
173|C-UKR |938458055|Welcome 27/09/99
105|C-YEM |934577345|FYI
67|F-1 |933350785|Click on any document listed below or the
documents tab at the left for a ...

Note that here while they are unique, they are not ordered according to
postedon. I suppose that I could do a SELECT INTO but that eats up a lot of
time. I'm trying to dynamically generate this list for a web page... It'd be
nice if the DISTINCT ON routine would return a list of distinct rows
regardless of the order, somehow...

Never retreat. Never surrender. Never cut a deal with a dragon.
_______________________________________________________________
Justin Long Executive Producer
616 Station Square Ct http://www.strategicnetwork.org
Chesapeake, VA 23320 Network for Strategic Missions
JustinLong(at)strategicnetwork(dot)org 977 Centerville Trnpk CSB 317
757-226-5011 Va Beach, VA 23463, USA