Identifying if records from Table A are also in Table B

[Kgraham01]

Hello, I am having trouble finding a solution for what doesn't feel like an unusual issue, I am new to power BI so I might be missing the obivious here. 

I am looking at two tables in Power BI desktop, and Table A which is a table of both customers and prospects and Table B contains our Budget. 

I wanted to add a column to Table A to identify which records have a Budget. Is there a simple DAX formula which will return a True/False or Y/N for which records have a budget? The relationship between the two tables is causing me issues because the prospects are are NULL in the column for customer number, since they do not yet have one. 

Any sugguestions or tip would be helpful. 

Thanks! 

[ryan_mayu]

could you pls provide some sample data and expected output?

[Kgraham01 · Accepted solution]

I think I might have figured it out. But would love a 2nd look. 

So table A would be 

Customer Number	Name
11111	Customer A
22222	Customer B
33333	Customer C
	Prospect 1
	Prospect 2

And Table B would be 

Customer Number	Name	Budget
11111	Customer A	500
22222	Customer B	600
11111	Customer A	200
22222	Customer B	100
11111	Customer A	400

I created a Many to Many relationship between the two tables using customer number 

Then added a column to Table A  with the fomula: 

IF('Table A'[Customer Number]IN DISTINCT('Table B'[Customer Number]),1,0)

Which was able to add a new column that shows a 1 if the the customer has a budget and a 0 if they have no budget. I believe I can then use this to create the measures and reports I need. 

Any sugguestions on making this easier, or more usable. I would appreciate. 

Thanks!