Need to fetch multiple values from the same table

Hello dsbuilder 

check out this solution. It uses Table.Group and AddColumn. This will write your requested data in every column, no only in the first 🙂

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMtQzVAjKTE5V0lFSAONYHRRBIBPIccopTYWJuHmGuWJTZaTgXpSamocwDaLGSCEgvySxJD+1GM0KFAkgF2iaf04KsmBIuKsPdrtQXRTi6qej4OrjGubqR1gx0PpYAA==", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [L1column = _t, L2column = _t, Number_ext = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"L1column", type text}, {"L2column", type text}, {"Number_ext", type text}}),
    #"Grouped Rows" = Table.Group(#"Changed Type", {"L1column"}, {{"AllRows", each _, type table [L1column=text, L2column=text, Number_ext=text]}}),
    #"Added Custom" = Table.AddColumn(#"Grouped Rows", "Conc", each Text.Combine([AllRows][#"Number_ext"])),
    #"Expanded AllRows" = Table.ExpandTableColumn(#"Added Custom", "AllRows", {"L1column", "Number_ext"}, {"L1column.1", "Number_ext"})
in
    #"Expanded AllRows"

Copy paste this code to the advanced editor in a new blank query to see how the solution works.

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Kudoes are nice too

Have fun

Jimmy