Looping a working DAX function in a calculated column

[Mathias_W]

Hi All,

I have a function that will look at a null field in column "Project Commit Cap" and lookup the value with the same ID and the next earlier date and give column "Project Commit Cap NoNulls" that value. DAX does not do it recursively so if there are 2 null values in a row I get a blank. In another language a simple while loop (while value is null do: XYZ) would solve this, but DAX does not support For/While loops?

How can i get the working DAX function to apply the filled in values and keep running until there are no more nulls?

Optionally how can i brute force it to run X number of times (maybe 10)? it wouldn't be a pretty solution but will get the job done

Example tables below are filtered to show only one 2 IDs, records of different IDs are between the records shown here so I cant do an excel-like function "take value from row below"

Here is the dax function that will fill in the previous value:

'ProjectCommitCap_NoNulls =
if(isblank('Project Story Data'[Projected Commitments Cap]),
LOOKUPVALUE('Project Story Data'[Projected Commitments Cap],'Project Story Data'[ID],'Project Story Data'[ID],
'Project Story Data'[Date of Data],CALCULATE(MAX('Project Story Data'[Date of Data]),FILTER('Project Story Data','Project Story Data'[ID]=EARLIER('Project Story Data'[ID])&&'Project Story Data'[Date of Data]<EARLIER('Project Story Data'[Date of Data])))),
'Project Story Data'[Projected Commitments Cap])'

Here is what the table looks like currently (only filling in one blank value gap:

ID	Date of Data	Projected Commitments Cap	ProjectCommitCap_NoNulls
3189	4/1/2019		$28,252.99
3189	2/25/2019	$28,252.99	$28,252.99
3189	1/14/2019
3189	12/24/2018		$27,820.85
3189	11/5/2018	$27,820.85	$27,820.85
3189	10/22/2018		$28,036.92
3189	10/15/2018	$28,036.92	$28,036.92
2485	10/15/2018		$11,114.51
2485	10/9/2018	$11,114.51	$11,114.51
3189	10/9/2018
3189	9/24/2018
3189	9/10/2018
3189	9/4/2018		$33,100,567.50
3189	8/27/2018	$33,100,567.50	$33,100,567.50
3189	8/13/2018		$31,229.54
3189	7/23/2018	$31,229.54	$31,229.54
3189	7/16/2018		$28,896.80
3189	7/9/2018	$28,896.80	$28,896.80
3189	6/25/2018	$29,790.51	$29,790.51
3189	6/18/2018		$0.00
3189	6/11/2018	$0.00	$0.00

Here is what I want it to look like:

ID	Date of Data	Projected Commitments Cap	ProjectCommitCap_NoNulls
3189	4/1/2019		$28,252.99
3189	2/25/2019	$28,252.99	$28,252.99
3189	1/14/2019		$27,820.85
3189	12/24/2018		$27,820.85
3189	11/5/2018	$27,820.85	$27,820.85
3189	10/22/2018		$28,036.92
3189	10/15/2018	$28,036.92	$28,036.92
2485	10/15/2018		$11,114.51
2485	10/9/2018	$11,114.51	$11,114.51
3189	10/9/2018		$33,100,567.50
3189	9/24/2018		$33,100,567.50
3189	9/10/2018		$33,100,567.50
3189	9/4/2018		$33,100,567.50
3189	8/27/2018	$33,100,567.50	$33,100,567.50
3189	8/13/2018		$31,229.54
3189	7/23/2018	$31,229.54	$31,229.54
3189	7/16/2018		$28,896.80
3189	7/9/2018	$28,896.80	$28,896.80
3189	6/25/2018	$29,790.51	$29,790.51
3189	6/18/2018		$0.00
3189	6/11/2018	$0.00	$0.00

Thanks! Let me know if i need to provide more detail 🙂

[Greg_Deckler · Accepted solution]

Looping is generally not permitted in DAX. However, I have written some blog articles on simulating looping in DAX that you might find useful:

https://community.powerbi.com/t5/Community-Blog/For-and-While-Loops-in-DAX/ba-p/636314

https://community.powerbi.com/t5/Community-Blog/Previous-Value-Recursion-in-DAX/ba-p/638320