PowerQuery - fill value in column based on condition

Hello JakubWiniarczk 

I've prepared a solution for you. This involves replacing empty cells with null and then apply a filldown.

Here the code

let
	Source = #table
	(
		{"Indeks","Description","Value"},
		{
			{"1","Opis1","Test"},	{"2","Opis2",""},	{"3","Opis3",""},	{"4","Opis4",""},	{"5","Opis4","Test2"},	{"6","Opis5",""},	{"7","Opis6",""},	{"8","Opis7","Test3"},	
			{"9","Opis7",""},	{"10","Opis8",""},	{"11","Opis9","Test4"},	{"12","Opis10",""}
		}
	),
    ReplaceEmptywithNull = Table.ReplaceValue(Source,"",null,Replacer.ReplaceValue,{"Value"}),
    FillDown = Table.FillDown(ReplaceEmptywithNull,{"Value"})
in
	FillDown

Copy paste this code to the advanced editor in a new blank query to see how the solution works. If this solution fits your need, copy and past a part of it and implement it in your query

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Kudoes are nice too

Have fun

Jimmy

Hi JakubWiniarczk ,

In power query, we can fill the column down as below.

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("Tc69CoAwDATgd8ncwTbp31O4uJWODm5CfX+k8SKdDj5y4VojT472+xozj3M81F2jAJypwAA2EIAYxAXmn6CaoNHOMiAZFEBGj1Xrogp+g5RfbHlFUz627dqg3l8=", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type text) meta [Serialized.Text = true]) in type table [Indeks = _t, Description = _t, Value = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Indeks", Int64.Type}, {"Description", type text}, {"Value", type text}}),
    #"Replaced Value" = Table.ReplaceValue(#"Changed Type","",null,Replacer.ReplaceValue,{"Value"}),
    #"Filled Down" = Table.FillDown(#"Replaced Value",{"Value"})
in
    #"Filled Down"

Alternatively, We can achieve that by DAX.

Column = 
VAR a = 'Table (2)'[Indeks]
VAR ind =
    CALCULATE (
        MAX ( 'Table (2)'[Indeks] ),
        FILTER (
            'Table (2)',
            'Table (2)'[Value] <> BLANK ()
                && 'Table (2)'[Indeks] <= a
        )
    )
RETURN
    CALCULATE (
        MAX ( 'Table (2)'[Value] ),
        FILTER ( 'Table (2)', 'Table (2)'[Indeks] = ind )
    )

Pbix as attached.