average without Zero - Power querry

Try this Daniff 

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMlDSUTIEYlOlWJ1oJSMgyxKFZwDnmYBZMJ4xkGUG5xlAVRqAeYZQnoVSbCwA", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [V1 = _t, V2 = _t, #"Another column" = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"V1", Int64.Type}, {"V2", Int64.Type}, {"Another column", Int64.Type}}),
    #"Added Average" = 
    Table.AddColumn(
        #"Changed Type", 
        "Average", 
        each
            let
                varList =  List.Select(Record.ToList(_), each _ > 0),
                varAverage = List.Sum(varList) / List.Count(varList)
            in
            if varAverage = null then 0 else varAverage
    )    
in
    #"Added Average"

It returns this:

Here is what it does:

1. It converts the current record to a list, so 0,1 for the first record, 2,9 for the second.
2. It then keeps only the values in the list > 1. So the first list becomes 1, the second remains 2,9.
3. It then divides the sum of the list by the count of items in the list for the average.
4. In the case of a record having 0, 0, or all 0's, it will return 0 instead of null.
5. This doesn't care how many columns you have. It just keeps the same logic over the entire record, so all columns.

How to use M code provided in a blank query:
1) In Power Query, select New Source, then Blank Query
2) On the Home ribbon, select "Advanced Editor" button
3) Remove everything you see, then paste the M code I've given you in that box.
4) Press Done
5) See this article if you need help using this M code in your model.