[QGIS-Developer] Virtual fields with relation_aggregate expressions

[Andreas Neumann]

Hi Nyall,

I tested recent master, which contains your fix about virtual fields 
with relation_aggregate expressions 
(https://github.com/qgis/QGIS/commit/4e5597ab72e689d117a980dd00efbf52558b95d5) 
, but unfortunately I am not able to display the aggregated values in 
the virtual field.

Here is my expression:

relation_aggregate(relation:='rel_anlage_sondengruppe',aggregate:='sum', 
expression:="anzahl_sonden")

The preview of the expression result in the expression editor works 
fine, but the values in the attribute table are all 'NULL' ;-)

-------------------

I also noticed a small error in the help text of the 
"relation_aggregate" expression:

the documentation always talks about a "calculation" parameter, but it 
only works with a parameter named "expression". See my example above.

So I believe the help text needs to be corrected.

Thanks,

Andreas