DAX Last Year to Date - powerbi

Question

So I know this question has been asked a few times, and I've religiously looked over different approaches, however I still don't quite understand why I'm getting an incorrect result.
Case: I have Sales Data from ~2016 -> 2019 (up until the 2/18/2019) I'm have a Measure to show me the YTD, however I'm looking for a measure for Last Years to date(the 18th in this particular circumstance).
Right now, I have this:
Total Sales LYTD =
CALCULATE (
[Total Sales],
SAMEPERIODLASTYEAR (
FILTER (
VALUES ( Sales[Completed Date] ),
Sales[Completed Date] <= MAX ( Sales[Completed Date] )
)
)
)
The logic to me makes sense, but I'm sure I'm missing something, has it appears it's grabbing the ENTIRE total of 2018 when in reality i'm looking for 01/01/2018 -> 2/18/2018
This is going to be dynamically uploaded with new sales data
What am I missing? Thank you so much!

Answer 1

Not sure I understand your table setup so lets look at this scenario and hopefully it helps.
Suppose you have the data in two tables, Sales and Calendar, and there's a 1:* relationship between the calendar and the sales tables. Then I would write the measures like this:
SalesToDateThisYear =
calculate(
Sum(Sales[Sales]);
Calendar[Year] = Year(Today())
)
and
SalesToDateLastYear =
var dateLastYear = Today() - 365
return
calculate(
Sum(Sales[Sales]);
Calendar[Year] = Year(dateLatsYear);
Calendar[Date] < dateLastYear
)
The two filter arguments are combined with a logic AND. So only dates from the first of last year to today's date last year will be included.
If you want to use the SamePeriod-function you can probably write something like this
SPLY =
calculate =
Sum(Sales[Sales]);
SamePeriodLastYear(
Filter(
Values(Calendar[Date]);
Calendar[Date] >= Date(year(today()); 1; 1) && Calendar[Date] < Today()
)
)
)
The SamePeriod-function takes a set of dates (this year) and converts them to dates last year.
Cheers