Standard Deviation on items sold

Hello,

I want to calculate the Standard Deviation for a specific product

For that, I have a sales table from the last 180 days with daily granularity 

(Date, product, vendor, items sold)

If a product had 10 items sold in day 1 and 0 items sold in day 2, it will only show up in day 1.

For that reason, I need to know how to take in consideration in a measure the days without sales ?

In SQL, it is just a matter of doing a cross join between date dimension and sales table, and then apply the standard deviation formula. But, what about PBI ? How can I do it in a measure ?

Thanks a lot

Diego