Sales - stock Calculation

hi,

I have a Sales table:

Order      Date               Product  Sales

and a Stock table:

Product    Quantity

How can I make a DAX measure to calculate the Material Requirement for each date?

Eg. 

Date                Product   Requirement

the tricky part is that the stock table does not have date column, meanwhile the Sales table has the Date column.

sample file is here:

https://1drv.ms/x/s!Aps8poidQa5zkvFwWm3YbzFb15bkTw

thanks