Referencing data from another row

[Thomas_DE]

I have a Table with the following structure

Title	Entry	Data
A	10	MasterData 1
A	23	SpecialData
A	54	null
B	10	MasterData 2
B	34	null
B	576	null
C	10	null
C	21312	null

What i want to achieve in Power Query M is that for some entries in the table i have "MasterData" which is always under Entry "10" for the corresponding Title, some may also have SpecialData which i don´t want to touch...

The Table i would want to have would be like this:

Title	Entry	Data
A	10	MasterData 1
A	23	SpecialData
A	54	MasterData 1
B	10	MasterData 2
B	34	MasterData 2
B	576	MasterData 2
C	10	null
C	21312	null

So i would need to somehow reference always the Data from Entry "10" for all null values of the same title data. It could also be in a new added column if that´s easier. Filldown is not helping in this case either unfortunately because i cannot restrict it to the same Title. I just found a working formula replacing the null value with an value of the same row... how can i shift that reference to always return the corresponding Title "10" Entry if there is one?

= Table.AddColumn(#"xxx", "Data", each if [Data] = null then [Entry] else [Data], type text)

This "[Entry]" i would need to point to the corresponding 10 entry of the same title...

Any hint how to do that is very appreciated! Thanks!

[wdx223_Daniel · Accepted solution]

NewStep=Table.Combine(Table.Group(PreviousStepName,"Title",{"n",each Table.ReplaceValue(_,"","",(x,y,z)=>x??_{[Entry=10]}?[Data],{"Data"})})[n])

[Thomas_DE]

Thanks! This is working as I need it, I don´t understand it yet but I´ll go through it step by step till i do.

[jbwtp]

Hi @Thomas_DE,

I think this does what you are after. Please try.

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WclTSUTI0ABK+icUlqUUuiSWJCoZKsToQGSNjIBFckJqcmZgDkoJLmJoAibzSnBywiBMWQ4zgMsYYak3NzZCFnGHaUUSMDI0NjeCCsQA=", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Title = _t, Entry = _t, Data = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Title", type text}, {"Entry", Int64.Type}, {"Data", type text}}),
    fTransform = (t as table) as table =>
        let 
            Transform = List.Skip(List.Accumulate(Table.ToRecords(t), {{null, {}}}, (a, n)=>  a &  (if n[Entry] = 10 then {{n[Data], n }} else {{List.Last(a){0}, if n[Data]="null" then Record.TransformFields(n, {{"Data", (x)=> List.Last(a){0}}}) else n }}))),
            Output = Table.FromRecords(List.Zip(Transform){1}, Value.Type(t))
        in
            Output,
    next = #"Changed Type",
    #"Grouped Rows" = Table.Combine(Table.Group(next, {"Title"}, {{"Count", fTransform}})[Count])
    in #"Grouped Rows"

Kind regards,

John