Solved: Lookup to value of previous year

Anonymous · ‎08-25-2022

Hi everyone,

I have the following table in PowerQuery:

Date	Value
01/01/2000	23655
01/01/2001	36985
01/01/2002	65987

I would like to add a colomn with the year-to-year growth. This means that for each row, I would look up the value of the year before and divide it and substract 1. I know how to do this with DAX, but in my use case I need to make use of M Query language and I am not finding any resources online. Could anyone help me with this?

Vijay_A_Verma · ‎08-25-2022

See the working here - Open a blank query - Home - Advanced Editor - Remove everything from there and paste the below code to test (later on when you use the query on your dataset, you will have to change the source appropriately. If you have columns other than these, then delete Changed type step and do a Changed type for complete table from UI again)

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMtQ31DcyMDBQ0lEyMjYzNVWK1YELGgIFjc0sLVAEjYCCZqaWFuZKsbEA", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Date = _t, Value = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Date", type date}, {"Value", Int64.Type}}),
    #"Added Index" = Table.AddIndexColumn(#"Changed Type", "Index", 0, 1, Int64.Type),
    #"Added Custom" = Table.AddColumn(#"Added Index", "%YoY", each try Number.Round([p=List.Buffer(#"Added Index"[Value]){[Index]-1}, YoY= ([Value]-p)/p*100][YoY],2) otherwise null, type number),
    #"Removed Columns" = Table.RemoveColumns(#"Added Custom",{"Index"})
in
    #"Removed Columns"

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View solution in original post

Vijay_A_Verma · ‎08-25-2022

See the working here - Open a blank query - Home - Advanced Editor - Remove everything from there and paste the below code to test (later on when you use the query on your dataset, you will have to change the source appropriately. If you have columns other than these, then delete Changed type step and do a Changed type for complete table from UI again)

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMtQ31DcyMDBQ0lEyMjYzNVWK1YELGgIFjc0sLVAEjYCCZqaWFuZKsbEA", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Date = _t, Value = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Date", type date}, {"Value", Int64.Type}}),
    #"Added Index" = Table.AddIndexColumn(#"Changed Type", "Index", 0, 1, Int64.Type),
    #"Added Custom" = Table.AddColumn(#"Added Index", "%YoY", each try Number.Round([p=List.Buffer(#"Added Index"[Value]){[Index]-1}, YoY= ([Value]-p)/p*100][YoY],2) otherwise null, type number),
    #"Removed Columns" = Table.RemoveColumns(#"Added Custom",{"Index"})
in
    #"Removed Columns"

👍 It's been a pleasure to help you | Help Hours: 11 AM to 9 PM (UTC+05:30)

How to get your questions answered quickly -- How to provide sample data