How to Lookup value from latest date for specific value

[SafeAnalyst]

Hi.

I have the following dataset where i would like to locate the 'Item Legder Entry Type' for each Item No based on the last posting date. I have the column 'Last Posting Date' and i would like to return the 'Item Ledger Entry Type' for that date.

It's possible that you have a solution where the Last Posting date isn't needed. 

Posting Date	Item Ledger Entry Type	Item No	Last Posting Date
28-09-2020	Purchase	EF0397	28-09-2020
08-07-2020	Negative Adjustment	EF0397	28-09-2020
23-06-2020	Consumption	EF0397	28-09-2020

My desired outcome is:

Posting Date	Item Ledger Entry Type	Item No	Last Posting Date
28-09-2020	Purchase	EF0397	28-09-2020

[Smauro · Accepted solution]

Hi @SafeAnalyst ,

Using [Last Posting Date] :

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMrLQNbDUNTIwMlBQ0lFSQAIBpUXJGYnFqUBhVzcDY0tzIANZdaxOtJIBkG8O5sM1+6WmJ5ZklqUqOKZklRaX5KbmleAzwchY18AM1QQ4cM7PKy7NLSjJzM/Da4QJjA+URHW1iYkRSANCAVi9EWnqgWwDQyDX0BIoB/deIpr3TMzNgAwktbGxAA==", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [#"Posting Date" = _t, #"Item Ledger Entry Type" = _t, #"Item No" = _t, #"Last Posting Date" = _t]),

    #"Keep Last Dates" = Table.SelectRows(Source, each [Posting Date] = [Last Posting Date])
in
    #"Keep Last Dates"

Using just [Posting Date] :

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMrLQNbDUNTIwMlBQ0lFSQAIBpUXJGYnFqUBhVzcDY0tzIANZdaxOtJIBkG8O5sM1+6WmJ5ZklqUqOKZklRaX5KbmleAzwchY18AM1QQ4cM7PKy7NLSjJzM/Da4QJjA+URHW1iYkRSANCAVi9EWnqgWwDQyDX0BIoB/deIpr3TMzNgAwktbGxAA==", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [#"Posting Date" = _t, #"Item Ledger Entry Type" = _t, #"Item No" = _t, #"Last Posting Date" = _t]),

    LastDates = Table.Group(Source[[Item No], [Posting Date]], {"Item No"}, {{"Max Date", each List.Max([Posting Date]), type date}}),
    #"Keep Last Dates" = Table.NestedJoin ( Source, {"Item No", "Posting Date"}, LastDates, {"Item No", "Max Date"}, "Remove", JoinKind.Inner),
    #"Remove Extra Column" = Table.RemoveColumns( #"Keep Last Dates", {"Remove"})
in
    #"Remove Extra Column"

[SafeAnalyst]

Thankt you @Smauro!

I have a question regarding the Table.NestedJoin part of the code. How do you merge the same table with an earlier version of it self? Is it only possible when writing the code or can you do that through the UI by pressing merge queries?

[SafeAnalyst]

Actually @AlB i have some issues with your code. It me be because i haven't expressed myself clearly enough.

I have added som more data to my example because your code only filters to the item numbers with the posting date of 29-09-2020.

Posting Date	Item Ledger Entry Type	Item No	Last Posting Date
28-09-2020	Purchase	EF0397	28-09-2020
08-07-2020	Negative Adjustment	EF0397	28-09-2020
23-06-2020	Consumption	EF0397	28-09-2020
24-09-2020	Purchase	EF0442	24-09-2020
22-09-2020	Purchase	EF0442	24-09-2020
09-01-2019	Negative adjustment	EF0476	09-01-2019

[Anonymous]

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMrLQNbDUNTIwMlBQ0lFSQAIBpUXJGYnFqUBhVzcDY0tzpVidaCUDoHpzsHq4cr/U9MSSzLJUBceUrNLiktzUvBJUPUbGugZmqHrgwDk/r7g0t6AkMz8PTZMJzGFAcVS3mJgYQZQYEVQClDcwBCoxtASKwx2aiOZQE3MzpdhYAA==", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [#"Posting Date" = _t, #"Item Ledger Entry Type" = _t, #"Item No" = _t]),
    #"Duplicated Column" = Table.DuplicateColumn(Source, "Posting Date", "Last Posting Date"),
    #"Grouped Rows" = Table.Group(#"Duplicated Column", {"Item No"}, {{"max Posting Date", each Table.Max(_, {"Posting Date"})}}),
    #"Expanded max Posting Date" = Table.ExpandRecordColumn(#"Grouped Rows", "max Posting Date", {"Posting Date", "Item Ledger Entry Type", "Last Posting Date"}, {"Posting Date", "Item Ledger Entry Type", "Last Posting Date"})
in
    #"Expanded max Posting Date"

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMrLQNbDUNTIwMlBQ0lFSQAIBpUXJGYnFqUBhVzcDY0tzpVidaCUDoHpzsHq4cr/U9MSSzLJUBceUrNLiktzUvBJUPUbGugZmqHrgwDk/r7g0t6AkMz8PTZMJzGFAcVS3mJgYQZQYEVQClDcwBCoxtASKwx2aiOZQE3MzpdhYAA==", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [#"Posting Date" = _t, #"Item Ledger Entry Type" = _t, #"Item No" = _t]),
    maxList=Table.ToRecords(Table.Group(Source, "Item No",{"Posting Date", each List.Max([Posting Date])})),
    tsr=Table.SelectRows(Source, each List.Contains(maxList, [[Item No],[Posting Date]]))
in
    tsr

[AlB]

Hi @SafeAnalyst 

Paste this code in a blank query to see the steps. #"Filtered Rows" is the relevant one

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMrLQNbDUNTIwMlBQ0lEKKC1KzkgsTgUyXd0MjC3NlWJ1opUMgGrMwWqA4n6p6YklmWWpCo4pWaXFJbmpeSWoqo2MdQ3MYKqd8/OKS3MLSjLz85BUxQIA", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [#"Posting Date" = _t, #"Item Ledger Entry Type" = _t, #"Item No" = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Posting Date", type date}, {"Item Ledger Entry Type", type text}, {"Item No", type text}}),

    #"Filtered Rows" = Table.SelectRows(#"Changed Type", each List.Max(#"Changed Type"[Posting Date])=[Posting Date])
in
    #"Filtered Rows"

Please mark the question solved when done and consider giving kudos if posts are helpful.

Contact me privately for support with any larger-scale BI needs, tutoring, etc.

Cheers 

[SafeAnalyst]

Thanks @AlB - It worked like a charm. I figured it would be quite simple 🙂