adding end date

[evadung]

Hello, I have a table with date, item, warehouse and quantity:

date	item	warehouse	quantity
6.10.2023	A	203	8
8.11.2023	A	203	7
3.6.2023	B	205	5
7.11.2023	B	205	8

I want to add "end date" so the table will look like this:

date	item	warehouse	quantity	end date
6.10.2023	A	203	8	8.11.2023
8.11.2023	A	203	7	null
3.6.2023	B	205	5	7.11.2023
7.11.2023	B	205	8	null

i tried
1) grouping by item and warehouse
2) add custom index table (0,1,)
3) delete all columns except index table + expand = table date, item, warehouse, quantity + index column
4) adding new index column 2 (index column + 1)
5) merging queries (index + index 2, item + item, warehouse + warehouse)
6) expand just date
in the newest date should be null but instead it looks like it choose random date 

thank you for your ideas

[tackytechtom · Accepted solution]

Hi @evadung ,

How about this:

I did something similar that you suggested: Group By Item with MAX on date and then joined that outcome with the original table. Rest was just some cleansing.

Here the code in Power Query M that you can paste into the advanced editor (if you do not know, how to exactly do this, please check out this quick walkthrough)

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMtMzNNAzMjAyVtJRcgRiIwMQy0IpVidayULP0BBTzhwsZ6xnBpNyAkuZAklTsJQ5kjaEHNDIWAA=", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [date = _t, item = _t, warehouse = _t, quantity = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"date", type date}, {"item", type text}, {"warehouse", Int64.Type}, {"quantity", Int64.Type}}),
    #"Grouped Rows" = Table.Group(#"Changed Type", {"item"}, {{"MaxDate", each List.Max([date]), type nullable date}}),
    #"Merged Queries" = Table.NestedJoin(#"Changed Type", {"item"}, #"Grouped Rows", {"item"}, "Grouped Rows", JoinKind.LeftOuter),
    #"Expanded Grouped Rows" = Table.ExpandTableColumn(#"Merged Queries", "Grouped Rows", {"MaxDate"}, {"Grouped Rows.MaxDate"}),
    #"Added Custom" = Table.AddColumn(#"Expanded Grouped Rows", "end date", each if [date] = [Grouped Rows.MaxDate] then null else [Grouped Rows.MaxDate]),
    #"Removed Columns" = Table.RemoveColumns(#"Added Custom",{"Grouped Rows.MaxDate"})
in
    #"Removed Columns"

[Edit]: You might need to add Warehouse to the GROUP BY as well...

Let me know if this solves your query 🙂

/Tom
https://www.tackytech.blog/
https://www.instagram.com/tackytechtom/