finding first record

[Arnoh]

Hi I have the following issue:

I have a table as below

id	source_id
100
101	100
102
103	102
104	101
105	104

I want to find the first record of 

so the result should look like this

id	source_id	first_id
100		100
101	100	100
102		102
103	102	102
104	101	100
105	104	100

Thanx for helping!

[ThxAlot]

Use recursive function in PQ

let
    Fx = (id, src) =>
    let pos = List.PositionOf(ID, src)
    in if pos > -1 then @Fx(ID{pos}, Src{pos}) else id,

    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMjQwUNJRUorVATENgUyQAIRnhJAwBksYQXkmYJ4hlGcK5pkoxcYCAA==", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [id = _t, source_id = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"id", Int64.Type}, {"source_id", Int64.Type}}),
    ID = #"Changed Type"[id], src=#"Changed Type"[source_id],
    
    Traced = Table.AddColumn(#"Changed Type", "Root", each fx([id], [source_id]))
in
    Traced

[Arnoh]

Hi Thanx for your reaction,

I can't get it working. I did try to copy your code in power query. 

Can you add extra information on how to create the recursive function in Power Query? 

Thanx 

[Kev74]

Hi try it :

first_id = IF(ISBLANK(LOOKUPVALUE('Table'[id], 'Table'[id], 'Table'[source_id])), 'Table'[id], LOOKUPVALUE('Table'[id], 'Table'[id], 'Table'[source_id]))

[Arnoh]

Hi Thanx for your reaction.

But this is n't going to work.