Cumulative sum in rows with Power query

Hi , Anonymous 

According to your description, you want to  "do an acumulative sum in rows with power query".

Here are the steps you can refer to :
(1)This is my test data:

(2)You can put this M code in the "Advanced Editor" to refer to :

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("bY7LCUAhDAR7ydmD+RjtJdh/GyYSH/LwMLAkw7JmgMTSoEB10CGHM1eYxSAE7debMgeylTDGdT0l9BnaG7OwPCpwyyHFFh2aa+jnujMX", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Installation = _t, #"1/1/2023" = _t, #"2/1/2023" = _t, #"3/1/2023" = _t, #"4/1/2023" = _t, #"5/1/2023" = _t, #"6/1/2023" = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Installation", Int64.Type}, {"1/1/2023", Int64.Type}, {"2/1/2023", Int64.Type}, {"3/1/2023", Int64.Type}, {"4/1/2023", Int64.Type}, {"5/1/2023", Int64.Type}, {"6/1/2023", Int64.Type}}),
    #"Unpivoted Other Columns" = Table.UnpivotOtherColumns(#"Changed Type", {"Installation"}, "Attribute", "Value"),
    #"Changed Type1" = Table.TransformColumnTypes(#"Unpivoted Other Columns",{{"Attribute", type date}}),
    Custom1 = Table.Group(#"Changed Type1",{"Installation","Attribute"},{"test",(x)=>List.Sum(Table.SelectRows(#"Changed Type1",(y)=> y[Installation]=x[Installation]{0} and y[Attribute]<=x[Attribute]{0})[Value])    }),
    #"Pivoted Column" = Table.Pivot(Table.TransformColumnTypes(Custom1, {{"Attribute", type text}}, "en-US"), List.Distinct(Table.TransformColumnTypes(Custom1, {{"Attribute", type text}}, "en-US")[Attribute]), "Attribute", "test", List.Max)
in
    #"Pivoted Column"

Then we can get the table you need:

Thank you for your time and sharing, and thank you for your support and understanding of PowerBI! 

Best Regards,

Aniya Zhang

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