Power Query: Conditional Combine Columns

hi, i recommend it create one column for each case using "Conditional Column"and after that "Merge Columns".

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WckxOzi/NKylW0lECoVidaCXn/LySxGSwkFtmUXGJX2Juqo6CTyKEBVPlk5qYAtUVUlmQahuj5JdaHgM1IbE4FSQXXJqUlZpcAmKllqUWZZZU2npkpmcoxcYCAA==", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type text) meta [Serialized.Text = true]) in type table [Table = _t, Fields = _t, Filter = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Table", type text}, {"Fields", type text}, {"Filter", type text}}),
    #"Added Custom" = Table.AddColumn(#"Changed Type", "Custom", each if [Fields] <> "" or [Filter] <>"" then [Table] & "?" else ""),
    #"Added Custom1" = Table.AddColumn(#"Added Custom", "Custom.1", each if [Fields] <> "" then "$select=" & [Fields] else ""),
    #"Added Custom2" = Table.AddColumn(#"Added Custom1", "Custom.2", each if [Filter] <> "" then "$filter=" & [Filter] else ""),
    #"Added Custom3" = Table.AddColumn(#"Added Custom2", "Custom.3", each if [Fields] = "" and [Filter] = "" then [Table] else ""),
    #"Inserted Merged Column" = Table.AddColumn(#"Added Custom3", "Merged", each Text.Combine({[Custom.3], [Custom], [Custom.1], [Custom.2]}, ""), type text)
in
    #"Inserted Merged Column"

Regards

Victor