Create column in table if it doesn't exist

Hi G_Whit-UK ,

List all the required columns in advance and refer to the steps below:

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WCkpNzi9KUTBU0lEKzi8tSk5VCK4sLknNVTBUCEvMKU0FihsqxerAFRrhUWiErNAYn4l65kqxsQA=", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [#"Record ID" = _t, Attribute = _t, Value = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Value", Int64.Type}}),
    #"Source System List" = {"Source System 1 Value","Source System 2 Value"},
    Custom1 = Table.Group(#"Changed Type",{"Record ID"}, List.Transform(#"Source System List", (y) => { y, (x) => try Table.SelectRows(x, each [Attribute] = y)[Value]{0} otherwise null }))
in
    Custom1

Best Regards,
Gao
Community Support Team

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