On Tue, May 24, 2016 at 12:12 PM, Manuel Gómez <targen@gmail.com> wrote:
On Tue, May 24, 2016 at 8:50 AM, David G. Johnston <david.g.johnston@gmail.com> wrote: > SELECT x, sum(i), sum(sum(i)) OVER (PARTITION BY x) FROM ( VALUES (a,1), > (a,2), (b,3) ) val (x,i) GROUP BY x > yields > a, 3, 6 > b, 3, 6
Thank you for this enlightening explanation! I was, however, very confused from this specific bit, so I tested it and indeed there must have been a typo:
postgres=# SELECT x, sum(i), sum(sum(i)) OVER (PARTITION BY x) FROM (VALUES ('a', 1), ('a', 2), ('b', 3)) val (x,i) GROUP BY x; x | sum | sum ---+-----+----- a | 3 | 3 b | 3 | 3 (2 rows)
Yes, that was me being careless. The partition in the window makes the sum(sum(i)) evaluate to 3
