One last question, using the "weather report" example, is it going to
improve performance for the DISTINCT ON query to add an index to the
location and time columns?
Thanks a lot,
Travis
On 3/16/07, Tom Lane <[EMAIL PROTECTED]> wrote:
"Travis Whitton" <[EMAIL PROTECTED]> writes:
> Given the following test table, I want to grab only the newest record
and
> disregard any older duplicates based on name. Is this the most efficient
way
> to do it?
No, it's gonna be pretty awful. The best way I know of involves
DISTINCT ON (see the "weather reports" example in the SELECT reference
page). Unfortunately that's a Postgres-only construct. If you want
something portable then you'll need something messy with subqueries...
regards, tom lane
