i am trying to create month over month sales, but unable to calculate the previous month sales
PrevMonthRev = CALCULATE(sum(salesdata[revenue]),PREVIOUSMONTH('date'[Month]))
date table:
| DateKey | Year | Month |
| 1 | 2015 | 1-Jan |
| 2 | 2015 | 1-Feb |
| 3 | 2015 | 1-Mar |
| 4 | 2015 | 1-Apr |
| 5 | 2015 | 1-May |
| 6 | 2015 | 1-Jun |
| 7 | 2015 | 1-Jul |
| 8 | 2015 | 1-Aug |
| 9 | 2015 | 1-Sep |
| 10 | 2015 | 1-Oct |
| 11 | 2015 | 1-Nov |
| 12 | 2015 | 1-Dec |
| 13 | 2016 | 1-Jan |
| 14 | 2016 | 1-Feb |
| 15 | 2016 | 1-Mar |
| 16 | 2016 | 1-Apr |
| 17 | 2016 | 1-May |
| 18 | 2016 | 1-Jun |
| 19 | 2016 | 1-Jul |
| 20 | 2016 | 1-Aug |
sales table
| DateKey | revenue |
| 1 | 123 |
| 2 | 234 |
| 3 | 345 |
| 4 | 456 |
| 5 | 567 |
| 6 | 678 |
| 7 | 789 |
| 8 | 8910 |
| 9 | 91011 |
| 10 | 101112 |
| 11 | 111213 |
| 12 | 121314 |
| 13 | 231 |
| 14 | 248 |
| 15 | 391 |
| 16 | 487 |
| 17 | 598 |
| 18 | 694 |
| 19 | 799 |
| 20 | 8980 |