Use Column header in calculated column

[A123-Chauhan]

Hi All,

I need help with the below requirement :
This is the sample file data I am currently working on. It contains the below columns having some blank values. I need an additional calculated column (Output column) that will contain the values of one column(Filename) with the header name of columns having blank values.

Below are the use cases:

In row 1, Col D is blank , so output is : Master/Col D

In row 5, Col C and Col D are blank, so output is : Master/Col C, Col D

In row 6, there is no blank column, so output is : BLANK()

Is there any way with DAX or in PowerQuery to achieve this?

[A123-Chauhan]

This is the sample data, columns can be more in future.

Filename	Col A	Col B	Col C	Col D	Output Col
Master	1	AA	101		Master/Col D
Master	2	BB		SQL	Master/Col C
Master	3		102	Power BI	Master/Col B
Source	4		103	SSIS	Source/Col B
Source	5	CC			Source/Col C, Col D
Master	6	DD	104	SSAS	BLANK()

Basically, I am looking for a dynamic solution that if any column in the table is blank that Column name has to be spotted in the output column. One shouldn't specifically mention any column name to check if it is blank or not i.e., the isblank operation should be performed row-wise.

I hope it helps @lbendlin 

[lbendlin · Accepted solution]

Thank you for the sample data.  Note that it has a lot of extra spaces so the following code may need some adjustments once you cleaned the data up.

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45W8k0sLkktUtJRMgRiR0cQwwDEVFCK1UGSNQJiJyewuI5ScKAPqqwxVMLQAKQuIL88tUjByROsJji/tCg5FShqAlcDUh0c7BmMKm8KxM7OUEVotpsBsYsLWLMJWLMjUHMsAA==", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Filename = _t, #"   Col A" = _t, #"   Col B" = _t, #"   Col C" = _t, #"  Col D" = _t]),
    CN =Table.ColumnNames(Source),
    #"Added Custom" = Table.AddColumn(Source, "Output Col",
  (k)=> let l =
  List.Generate(()=>[x=1,y=""], 
      each [x] < List.Count(CN), 
      each [x=[x]+1, y=[y] & (if Record.Field(k,CN{[x]}) > " " then "" else ", " & CN{[x]})],
      each [y] & (if Record.Field(k,CN{[x]}) > " " then "" else ", " & CN{[x]})
  ),
  m = try Record.Field(k,CN{0}) & "/" & Text.Range(l{List.Count(CN)-2},2) otherwise null
  in m
)
in
    #"Added Custom"

How to use this code: Create a new Blank Query. Click on "Advanced Editor". Replace the code in the window with the code provided here. Click "Done".

[lbendlin]

You cannot do that in DAX, but it is possible to do in Power Query. Please provide sanitized sample data that fully covers your issue. If you paste the data into a table in your post or use one of the file services it will be easier to work with.