SQL query to DAX Measure conversion

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("bY9LCsAgDETvkrWQxDFgzyLe/xottUhwun3MdwxxU7hWqyZFmsxyICzkCjtUGcWL2kd8+zJZtouCemoL0gRP4rKgIFDQzxGQ7Vk0bw==", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [#"Report Date" = _t, EDWCustomerID = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Report Date", type date}, {"EDWCustomerID", Int64.Type}}),
    #"Grouped Rows" = Table.Group(#"Changed Type", {"EDWCustomerID"}, {{"ar", each let t = Table.AddIndexColumn(Table.Sort(_, {"Report Date", Order.Ascending}),"Index",1,1), max = List.Max(t[Index]) in Table.AddColumn(t, "Marker", each if [Index]=max then 1 else 0)}}),
    #"Expanded ar" = Table.ExpandTableColumn(#"Grouped Rows", "ar", {"Report Date", "Index", "Marker"}, {"Report Date", "Index", "Marker"})
in
    #"Expanded ar"