stock calculation

[mordonez]

Hello  , i have a simple problem but i cant find a simple answer :
I tried to look on older posts but i couldnt find a solution to mi problem : 

I have a model where i have : 

Sales in : the sales from mi compañy to resellers

Sales Out: the sales from the resellers to end users

Initial stock : the stock on hand reported by the resellers at 01/01/2020 

I need to calculate the stock by  adding the sell in and sustracting the sell out : 

Example : 

initial stock  productA in reseller A =10000 to that value i have to add the sell in and sustract the sell out 

01/01/2020 stock=10000

sales in jan/2020=5000

Sales out in jan/2020=7000

stock in feb/2020= 10000+5000-7000=8000<then , this should be the initial stock in february so :

sales in feb/2020=2000

sales out feb/2020=5000

stock in march/2020=8000+2000-5000=5000 , and so on 

i have a sales in table with dates and sku and reseller number , also i have a sales out table with the same dimentions , calendar table , and product table

TY!!!

[Anonymous]

Please place a link to a model with your tables. Just anonymize the data that can't be exposed. I don't want to create the tables you're referring to by hand...

Best
D