Power Query (M) Table.SelectRows with Multiple Variables

Question

I'm writing some month over month aggregations for the value column.

Sample Data Link

I've written the monthly cumulative function without too much trouble:

 Table.AddColumn(#"Sorted Rows1", "Cumulative Value", each List.Sum(
 Table.SelectRows(
         #"Sorted Rows1", 
         (x) => x[Month Start] <= [Month Start]
         )
 [Value]), type number)

But am running into difficulties creating the MOM aggregation with the region included.

 Table.AddColumn(#"Added Custom2", "Property Region Cumulative Value", each List.Sum(
 Table.SelectRows(
         #"Added Custom2", each 
         (x) => x[Month Start] <= [Month Start]
         ,(x) => x[Property Region] = [Property Region]      
         )
 [Value]))

Any ideas on how to rewrite the criteria syntax to achieve the correct result?

Answer 1

This works fine (though your desired output seems wrong)

let  Source = Excel.CurrentWorkbook(){[Name="Table4"]}[Content],
#"Sorted Rows1" = Table.TransformColumnTypes(Source,{ {"Value", type number}}),
#"Added Custom1" = Table.AddColumn( #"Sorted Rows1","Cumulative Value",(x)=>List.Sum(Table.SelectRows( #"Sorted Rows1", each [Month Start] <= x[Month Start] and x[Property Region] = [Property Region])[Value]))
in  #"Added Custom1"