create a column that does cumulate sum on another column with 2 conditions

[mahsan_ojaghian]

Hi guys!

I want to create a column that does cumulate sum on another column with 2 conditions:

1 ) when ID changes this function that cumulates values resets 

2 ) And when sum of values is negative resets again and returns 0 and starts again with positive value.

 i NEED YOUR HELP as soon as possible.

[Vijay_A_Verma · Accepted solution]

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("bcpBDoAgDAXRu3QNCVQtdKl4C9L7X0OxCd8Fu5fJ9E4nBVIlC07hyd15jZo/tlHrJKPGCm8JB6P6cL/MsmLUY5kLzKD8jpyQC5k9", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [ID = _t, Value = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"ID", type text}, {"Value", Int64.Type}}),
    ListOfIDs = List.Buffer(#"Changed Type"[ID]),
    ListOfValues = List.Buffer(#"Changed Type"[Value]),
    //Function Start
    fxGetCumTotal=(ListOfIDs, ListOfValues)=>
        let
            FunctionResult = List.Generate(()=>[x=ListOfValues{0},i=0], each [i]<List.Count(ListOfValues), each [i=[i]+1, x=(if ListOfIDs{i}=ListOfIDs{[i]} then List.Max({0,[x]}) else 0) + ListOfValues{i}], each List.Max({0,[x]}))
        in
            FunctionResult,
    //Function End
    Result = Table.FromColumns(Table.ToColumns(#"Changed Type")&{fxGetCumTotal(ListOfIDs, ListOfValues)},Table.ColumnNames(#"Changed Type")&{"CumulativeTotal"})
in
    Result

[mahsan_ojaghian]

Thank you Vijay Your Solution is Perfect!!!!!!