I am currently using data defined properties and labeling to present pipes based on diameter. I now have a dictionary table that has id's for every combination of diameter and material and I'm using it with the value relation widget.
I must find a way to access the value represented by the key in the diameter || material field.
An ugly way that solves this would be to use:
CASE WHEN id_material_diam in (id1, id2) THEN result_formula_containing_diameter WHEN id_material_diam diameter in (id3...) THEN ... END
Is there an elegant way that I can access the actual values for which the ID is the key?
I am using QGIS 2.2 Valmiera