Previous Month

Hello BI users,

I have a problem which has many related posts but still couldnt get my chart to work. So any help would be appreciated

I have to show a value of total sales which is already calculated and stored in my table for each month(one value for every month of the year as 2017-05-01 for may and 2017-04-01 for april etc.). In BI, Current date(filterdate) which has a format yyyy-mm-dd is selected by the slicer

filterdate = format(DATE(erie_sale[YearD],erie_sale[MonthD],1),"yyyy-mm-dd")

and previous month and sales is calculated as below

PreviousMonth = PREVIOUSMONTH(erie_sale[filterdate])

PreviousSales = CALCULATE(SUM(erie_sale[Total]),PREVIOUSMONTH(erie_sale[filterdate]))

Uptil here the data shows fine in charts . but the problem is when I add month and year slicer extracted from the newdate (stored in sql as date type) it doesnot show me the correct data. It only shows me current month data the PreviousSales shows blank

MonthD = MONTH(erie_sale[newdate])

YearD = Year(erie_sale[newdate])

According to my understanding it shouls make a filter date from the month and year selected in slicer and 1 is passed expilictly as all dates are just the 1st of the month. then it should calculate previous month (which is working absolutely fine) and then measure PreviousSales should get calculated (which is not working in the case when only month and year is selected from the slicer ).