Check if value exists across DirectQuery - Import

Hi,lbendlin 

Thanks for your concern about this issue.

TREATAS can be used in other situations, but DirectQuery mode really doesn't support TREATAS.

And I would like to share some additional solutions below.

Hi,crobson29 

I am glad to help you.  

According to your description, you want to check if value exists across DirectQuery – Import? 

If I understand you correctly, then you can refer to my solution. 

Since TREATAS is not supported in DirectQuery mode, consider using a LEFT OUTER JOIN in the query that loads the data into the model. 

Here's a little example that I hope you find helpful. 

In the Power Query Editor click Merge Queries: 

Select the corresponding table and corresponding field PO, and then select Left Outer in the Join kind. 

Click on the red circle in the picture to expand the table: 

Mismatched PO values are displayed as null values: 

Here's some official documentation, hope it helps:

Tutorial: Shape and combine data in Power BI Desktop - Power BI | Microsoft Learn

Merge queries overview - Power Query | Microsoft Learn

I hope my suggestions give you good ideas, if you have any more questions, please clarify in a follow-up reply.

Best Regards,
Fen Ling,

If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.