Forum Discussion
How to do a running Sum by group in Power Query?
Hi Everyone, I am trying to do a running sum by group in Power Query (m language). Thank you. All solutions I found was to use DAX which I cannot use for my data at this time. Here is what my ...
You can use this query (assuming you want to group on "BU"):
let Source = Table1, TableType = Value.Type(Table.AddColumn(Source, "Running Sum", each null, type number)), #"Grouped Rows" = Table.Group(Source, {"BU"}, {{"AllData", fnAddRunningSum, TableType}}), #"Expanded AllData" = Table.ExpandTableColumn(#"Grouped Rows", "AllData", {"Location", "Month", "Cost", "Running Sum"}, {"Location", "Month", "Cost", "Running Sum"}) in #"Expanded AllData"With function fnAddRunningSum:
(MyTable as table) as table =>
let
Source = Table.Buffer(MyTable),
TableType = Value.Type(Table.AddColumn(Source, "Running Sum", each null, type number)),
Cumulative = List.Skip(List.Accumulate(Source[Cost],{0},(cumulative,cost) => cumulative & {List.Last(cumulative) + cost})),
AddedRunningSum = Table.FromColumns(Table.ToColumns(Source)&{Cumulative},TableType)
in
AddedRunningSum
You can use this query (assuming you want to group on "BU"):
let
Source = Table1,
TableType = Value.Type(Table.AddColumn(Source, "Running Sum", each null, type number)),
#"Grouped Rows" = Table.Group(Source, {"BU"}, {{"AllData", fnAddRunningSum, TableType}}),
#"Expanded AllData" = Table.ExpandTableColumn(#"Grouped Rows", "AllData", {"Location", "Month", "Cost", "Running Sum"}, {"Location", "Month", "Cost", "Running Sum"})
in
#"Expanded AllData"
With function fnAddRunningSum:
(MyTable as table) as table =>
let
Source = Table.Buffer(MyTable),
TableType = Value.Type(Table.AddColumn(Source, "Running Sum", each null, type number)),
Cumulative = List.Skip(List.Accumulate(Source[Cost],{0},(cumulative,cost) => cumulative & {List.Last(cumulative) + cost})),
AddedRunningSum = Table.FromColumns(Table.ToColumns(Source)&{Cumulative},TableType)
in
AddedRunningSum
MarcelBeug Thanks for this, absolute lifesaver! I think I spent half a day trying to figure out how to do this on my report before stumbling upon this thread.