Summing up attributes overlapping polygons in QGIS

Question

I have large single layers with many features overlapping, like this:

Where the features overlap I want the attributes added together. I've managed to count the number of overlap polygons by doing union then aggregate, I'll have this result:

but I'd also like to manage to have an output with the "sum" of the zone descriptions for each polygon overlap.

Answer 1

You can use overlay_intersects on the aggregated layer

array_to_string(overlay_intersects( 'conflits',"zone_description"))