Order (count) based on distinct ID

See if this works chris12345 

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMlSK1UEljZBIY2xkLAA=", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [ID = _t]),
    #"Grouped Rows" = 
        Table.Group(
            Source, 
            {"ID"}, 
            {
                {"Order", each Table.AddIndexColumn(_, "Order", 1, 1, Int64.Type)}
            }
    ),
    #"Expanded Order" = Table.ExpandTableColumn(#"Grouped Rows", "Order", {"Order"}, {"Order"}),
    #"Changed Type" = Table.TransformColumnTypes(#"Expanded Order",{{"Order", Int64.Type}})
in
    #"Changed Type"

It returns this.

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.

Hi, chris12345 

Based on your description, I created data to reproduce your sceanrio. The pbix file is attached in the end.

Table:

You may apply the following transformations in Power Query. Here are the m codes in 'Advanced Editor'.

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMlSK1UEljZBIY2xkLAA=", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [ID = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"ID", Int64.Type}}),
    Custom1 = Table.Group(#"Changed Type",{"ID"},{"Order",(x)=> List.Generate(
    ()=>1,
    each _<=Table.RowCount(x),
    each _+1
   ) 
   }
),
    #"Expanded Order" = Table.ExpandListColumn(Custom1, "Order"),
    #"Changed Type1" = Table.TransformColumnTypes(#"Expanded Order",{{"Order", Int64.Type}})
in
    #"Changed Type1"

Result:

Best Regards
Allan

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