calculate multiple filtered values from same column

Hello Anonymous 

 

in power query you can work with index-column and grouping. Here an example that shows you how to handle your puzzle

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMlTSUUqKNzEAUobmQMLYyFQpVidayQhJ3BIkbmAAFgepT4s3BpKmIGxsBFcNETUCESYgQ2IB", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [week = _t, product_id = _t, stock = _t, sales = _t]),
    #"Sorted Rows" = Table.Sort(Source,{{"product_id", Order.Ascending},{"week", Order.Ascending}}),
    #"Changed Type" = Table.TransformColumnTypes(#"Sorted Rows",{{"week", Int64.Type}, {"product_id", type text}, {"stock", Int64.Type}, {"sales", Int64.Type}}),
    #"Added Index" = Table.AddIndexColumn(#"Changed Type", "Index", 1, 1),
    #"Grouped Rows" = Table.Group
    (
        #"Added Index", 
        {"product_id"}, 
        {
            {
                "AllRows", 
                (tbl)=> Table.RemoveColumns(Table.AddColumn(tbl, "TotalBought", (add)=> let stockpreviousweek = try Table.SelectRows(tbl,  each [Index]= add[Index]-1)[stock]{0} otherwise 0 in add[stock]- stockpreviousweek + add[sales]), {"Index"})
            }
        }
    ),
    #"Expanded AllRows" = Table.ExpandTableColumn(#"Grouped Rows", "AllRows", {"week", "stock", "sales", "TotalBought"}, {"week", "stock", "sales", "TotalBought"})
in
    #"Expanded AllRows"

 

Copy paste this code to the advanced editor in a new blank query to see how the solution works.

If this post helps or solves your problem, please mark it as solution (to help other users find useful content and to acknowledge the work of users that helped you)
Kudoes are nice too

Have fun

Jimmy

 

Hi, Anonymous 

 

Based on your description, I created data to reproduce your scenario. The pbix file is attached in the end.

Table:

 

You may create a custom column with the following m codes.

let 
week = [Week],pid = [Product_id],
laststock = 
try
Table.SelectRows(#"Changed Type",each [Product_id]=pid and [Week]=week-1)[Stock]{0}
otherwise 
0
in 
[Sales]+[Stock]-laststock

 

Result:

 

Best Regards

Allan

 

If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.