Group by 2 fields in "Add autoincremental field" in QGIS Modeler

Question

I'm creating a model in Modeler in QGIS3.4. I want to use a "Add autoincremental field" tool. I want to group my field by two other fields (it works when I set it "normally", not in Modeler). I think I have an error in syntax. I work in a polish version, so it is a window of "Add autoincremental field" opened through Modeler.

Now we're interested in a "Grupuj wartości według" -> it's "Group values by". I want to group by 2 fields: "sekcja" (it's integer filed) and "numer_inwe" (it's string field, but filled with numbers, so we can switch it to integer as well). When I do it separatly it works, but the problem appears when I want to use both fields to group my table.

What syntax should I use if i want to group my table by 2 fields?

Answer 1

It requires a string list as input:

['sekcja', 'numer_inwe']

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But if you're going to use it through the modeler, might I suggest using the Vector field input parameter which can be set to accept multiple fields. You can connect this parameter to the "Add autoincremental field" tool. Then when you run the model, you can simply choose the fields you want grouped from a checkbox list instead of having to manually type the field names in.