[Qgis-developer] have aggregate/window expressions ever been discussed?

Andreas Neumann a.neumann at carto.net
Tue May 27 01:28:13 PDT 2014


We would definitely need this functionality for our application modules
- we need functions like "min", "max", "mean", "sum", "average" to work
on 1:n relations.

Now that we have relations in QGIS, I think that aggregate functions are
a logical next step. Something to seriously consider in 2.6.


Am 23.05.2014 17:34, schrieb G. Allegri:
> Recently I had to calculate the relative dimension of a polygon relative to
> the others of the same class. I know there are a lot of way to do it,
> inside and outside QGIS, but I wondered if field calculator (and
> expressions in general) couls be extended to accompish this kind of tasks.
> The approach would be something similar WINDOW functions in Postgresql [1],
> where for each record a new value will be calculated on the basis of other
> records (filtered or not).
> Has this ever been discussed? Is it something that could fit QGIS
> expressions?
> giovanni
> [1] http://www.postgresql.org/docs/9.1/static/tutorial-window.html
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