Calculated Column - DATEDIFF - Days Since Promo Start

Hi, 
I have two tables - one for sales, and one for promotions we run. 

Sales table includes following columns:

Promotions table consists of only two columns:

I'm looking to add a calculated column 'PromotionDay' to the Sales table to return how many days into the Promotion the order was placed. Is this relatively simple to calculate?

example below:

Promotion Table includes record: PromotionCode = 'SPRING22', PromoStartDate = '01 March 2022'

Sales Table would have the below record

Thanks in advance.