Thom, depesz, silly, > SELECT DISTINCT ON (id_bf) id_bf, wert, letztespeicherung > FROM rfmitzeit > ORDER BY id_bf, letztespeicherung ASC; yes, that does work. I put it in the real world query (my example was reduced to the relevant parts), and it provides an impressive speedup (down from 2234 to 1600ms on the worst possible dataset with worst possible disk/cache situation) And I learned that DISTINCT ON (xxx) .... order by zzzz will first do the order by, and then definitely take every "first row" of the ordered result. My expection of DISTINCT on (id_bf) was "give me ONLY ONE of the rows with every id_bf", I was not aware of the fact that it will give me THE FIRST of the 'ordered by' result set. Thanks to all who helped me learn today! Harald (and sorry for leaving HTML on on some of the mails) -- GHUM Harald Massa persuadere et programmare Harald Armin Massa Spielberger Straße 49 70435 Stuttgart 0173/9409607 no fx, no carrier pigeon - %s is too gigantic of an industry to bend to the whims of reality -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
