Life sure would be easier if that were the case Michal, but no... that is not the case here. The sum is not a simple sum, it is a sum of all elements having a lower or equal A and the same C. This is a "cumulative sum" as pointed out by others. 2009/4/15 Michal Politowski <mpol+pg@xxxxxxx>: > On Wed, 15 Apr 2009 15:32:42 +0100, Shug Boabby wrote: >> I simplified my problem a little too much and now I'm stuck trying to >> use cumulative_sum(). My schema is not only A, B but also has a C >> >> A B C >> 1 0 1 >> 2 1 1 >> 3 0 1 >> 4 2 1 >> 5 1 1 >> 1 0 2 >> 2 1 2 >> 3 0 2 >> 4 2 2 >> 5 1 2 >> >> and I want to be able to do the cumulative sum only when C is the same. E.g. >> >> A funkySumB C >> 1 0 1 >> 2 1 1 >> 3 1 1 >> 4 3 1 >> 5 4 1 >> 1 0 2 >> 2 1 2 >> 3 1 2 >> 4 3 2 >> 5 4 2 > > If I understand the problem correctly, why not just something like this?: > > SELECT t1.a, sum(t2.b), t1.c FROM abc t1 JOIN abc t2 ON t2.a <= t1.a AND > t2.c=t1.c GROUP BY t1.a, t1.c; -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
