Andreas Kretschmer <akretschmer@xxxxxxxxxxxxx> wrote: > > they are being done over all rows. In this particular example you > > happen to get the same result, but that's just because "avg(foo) over > > partition by foo" is a dumb example --- it will necessarily just yield > > identically foo. In more realistic computations the results would be > > different. > > Okay, i believe you now ;-) > > I will try to find a case with different results ... I have got it! test=# select * from values; id | value ----+------- 1 | 10 2 | 20 3 | 30 4 | 40 5 | 50 6 | 60 7 | 70 8 | 80 9 | 90 (9 rows) Time: 0.240 ms test=*# select id, sum(value) over (order by id) from values where id = 5; id | sum ----+----- 5 | 50 (1 row) Time: 0.352 ms test=*# select * from (select id, sum(value) over (order by id) from values) foo where id = 5; id | sum ----+----- 5 | 150 (1 row) Time: 0.383 ms Andreas -- Really, I'm not out to destroy Microsoft. That will just be a completely unintentional side effect. (Linus Torvalds) "If I was god, I would recompile penguin with --enable-fly." (unknown) Kaufbach, Saxony, Germany, Europe. N 51.05082°, E 13.56889° -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
