Prior year sales by store

Hi guys,

I am trying to find out prior year sales by stores.

I have a 2017 and 2018 data tables by daily sales. If a store was closed in 2017, there will be no data in 2018. 

I have also created a master list store table which is able to pull current week sales and prior year 2017 sales. But the problem is that if the store was closed in 2017, there will be no sales reflected in current year which is correct, but it does not show the prior year sales in 2017. This is incorrect. There should be some sales amount in the prior year sales even though there is no sales in 2018. 

May i know what is the problem here? 

Thanks