Plotting calculated field from two tables over time in a line graph

[awu3639]

Currently, I have this measure I created using two different tables. Commission per unit sold = SUM ( Table1[total commission] )  / SUM ( Table2[units sold] ). How can I show this measure over time on a line graph if Table 1 and Table 2 each have a month column? For some reason, no matter if I plot Table1[month] by commission per unit sold or Table2[month] by commission per unit sold, neither of those work. I get an infinity in it, but the measure commission per unit sold itself works without the line graph. 

[Anonymous · Accepted solution]

Create a Date Table and then create a relationship between the date table and these two tables. 

Take a look: https://www.excelcampus.com/tables/calendar-table-explained/