Sort by date and provide unique identifier

Hi Anonymous, try this:

Result:

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WckwuySzLLKlUyM9LVdJRstA31jcyMDIBMg1NEWwzhfLU1GylWB0kDSXl+SBVBhBVRhC2CYydX1qCpjyjKBVkgyHCVGP8FqTllxaBNJgj6TDA1BILAA==", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Activity = _t, #"Start date" = _t, #"End date" = _t, #"Within 6 weeks" = _t]),
    #"v1_Changed Type" = Table.TransformColumnTypes(Source,{{"Start date", type date}, {"End date", type date}}, "sk-SK"),
    #"v1_Added Index" = Table.AddIndexColumn(#"v1_Changed Type", "Index", 0, 1, Int64.Type),
    #"v1_Grouped Rows" = Table.Group(#"v1_Added Index", {"Within 6 weeks"}, {{"All", each Table.AddIndexColumn(Table.Sort(_, {"Start date", Order.Ascending}), "Unique ID", 1, 1, Int64.Type) , type table}}),
    v1_CombinedTables = Table.Combine(#"v1_Grouped Rows"[All]),
    v1_ReplaceValues = Table.ReplaceValue( v1_CombinedTables,
      each [Within 6 weeks],
      null,
      (x,y,z)=> if y = "out" then null else x,
      {"Unique ID"} ),
    #"v1_Sorted Rows" = Table.Sort(v1_ReplaceValues,{{"Index", Order.Ascending}}),
    #"v1_Removed Columns" = Table.RemoveColumns(#"v1_Sorted Rows",{"Index"})
in
    #"v1_Removed Columns"