Bug report #20142
Numeric calculation in "Merge selected features" dialog does not work
|Affected QGIS version:||3.3(master)||Regression?:||Yes|
|Operating System:||Easy fix?:||No|
|Pull Request or Patch supplied:||No||Resolution:||worksforme|
|Crashes QGIS or corrupts data:||Yes||Copied to github as #:||27963|
Select two features and click on "merge selected features" button
In the new dialog, for a numeric field try to use statistics functions like sum, count or whatever. The field in the "Merge" row becomes empty. If you try some statistics on a literal field you get the result in the field.
It's not simply a display issue given that if you do the merge, you get 0 in the numeric field.
I check "data corruption" as this is a tool that applies in-place modification and gives a wrong value you can not easily check later on/or rebuild.