On Thu, Aug 28, 2003 at 17:10:31 -0700, Ken Geis <[EMAIL PROTECTED]> wrote: > The query I want to run is > > select stock_id, min(price_date) from day_ends group by stock_id;
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The fast way to do this is: select distinct on (stock_id) stock_id, price_date order by stock_id, price_date; > Also, to get the MIN for a given group, not all values of the index need > to be seen. Must pgsql do a full scan because it treats all aggregates > in the same way? Are MIN and MAX used often enough to justify special > treatment, and could that be cleanly implemented? Perhaps the aggregate > function can request the data in a certain order, be told that it is > being passed data in a certain order, and return before seeing the > entire set of data. Yes, max and min are not treated special so they don't benefit from indexes. This has been discussed repeatedly in the archives. ---------------------------(end of broadcast)--------------------------- TIP 4: Don't 'kill -9' the postmaster
