How to sum multiple rows from another table

Can you provide some sample data jk8979356 per the links below? For a rough overview on the direction to go, see this code:

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WSlTSUTIEYlMgtlSK1YlWSgKyjKAi5uZgoWQg0xiIzYDYAiySAmQVgRSAFcbGAgA=", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Subsidiary = _t, Category = _t, #"2019 Sales" = _t, #"2020 Sales" = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"2019 Sales", Int64.Type}, {"2020 Sales", Int64.Type}}),
    #"Unpivoted Other Columns" = Table.UnpivotOtherColumns(#"Changed Type", {"Subsidiary", "Category"}, "Attribute", "Value"),
    #"Extracted First Characters" = Table.TransformColumns(#"Unpivoted Other Columns", {{"Attribute", each Text.Start(_, 4), type text}}),
    #"Renamed Columns" = Table.RenameColumns(#"Extracted First Characters",{{"Attribute", "Year"}, {"Value", "Sales"}}),
    #"Changed Type1" = Table.TransformColumnTypes(#"Renamed Columns",{{"Year", Int64.Type}})
in
    #"Changed Type1"

Turns this:

into this:

Which is where MattAllington was going as far as properly modeling your data before bringing it into the Data Model. Now you can connect that to a Date Table and do all sorts of things easily.

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.

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