Power Query M - Custom Column for Rolling 28 Days Sales

0
votes

I'm looking for some Power Query help. I have a huge set of sales data for 40k products over one year. For each product on each day I need to add a 28 day sales column.

I essentially want to do a sumifs like the below but in M.

=SUMIFS([SALES],[Product Code],[This Product Code],[Date],<=[This Date],[Date],>=[This Date]-28))

2
powerquerym

2 Answers

1
votes

Try this then, it should work but would likely do so at a crawl

 let Source = Excel.CurrentWorkbook(){[Name="Table1"]}[Content],
 #"Changed Type" = Table.TransformColumnTypes(Source,{{"Sales", Int64.Type}, {"Product Code", type text}, {"Date", type date}}),
 TotalAmountAdded = Table.AddColumn(Source, "Total Amount", (i) => List.Sum(Table.SelectRows(Source, each ([Product Code] = i[Product Code]  and [Date]<=i[Date] and [Date]>=Date.AddDays(i[Date],-28)))[Sales]), type number    )
 in TotalAmountAdded
0
votes

Add a custom column with date logic (based on your sample sumif formula), filter the new column to get the relevant rows, then group by product code and sum Sales. Assuming source data is in Table1 with three columns (Sales,Product Code, Date) the code would be

let Source = Excel.CurrentWorkbook(){[Name="Table1"]}[Content],
#"Changed Type" = Table.TransformColumnTypes(Source,{{"Sales", Int64.Type}, {"Product Code", type text}, {"Date", type date}}),
#"Added Custom" = Table.AddColumn(#"Changed Type", "AddMe", each if [Date]<=DateTime.Date(DateTime.LocalNow()) and [Date]>=Date.AddDays(DateTime.Date(DateTime.LocalNow()),-28) then 1 else 0),
#"Filtered Rows" = Table.SelectRows(#"Added Custom", each ([AddMe] = 1)),
#"Grouped Rows" = Table.Group(#"Filtered Rows", {"Product Code"}, {{"ProductSales", each List.Sum([Sales]), type number}})
in  #"Grouped Rows"