Exam PL-300 topic 2 question 97 discussion

Actual exam question from Microsoft's PL-300

Question #: 97
Topic #: 2

You have a Power BI model that contains two tables named Sales and Date. The Sales table relates to the Date table by using a many-to-one relationship. The Sales table contains the following columns:

• Date
• Product
• SalesAmount

You need to create a DAX measure for a rolling 31-day sales total that will return the total sales amount for a selected date and the previous 30 days.

Which DAX expression should you use?

A. CALCULATE(SUM(Sales[SalesAmount]), DATEADD(Date[Date], -30, DAY))
B. CALCULATE(SUM(Sales[SalesAmount]), DATESBETWEEN(Date[Date], Max('Date'[Date])-30, Max('Date'[Date])))
C. CALCULATE(SUM(Sales[SalesAmount]), DATESMTD(Date[Date]))
D. CALCULATE(SUM(Sales[SalesAmount]), DISTINCTCOUNT(Date[Date]) = 31)

Show Suggested Answer

Suggested Answer: B 🗳️

by nelrosell at Sept. 6, 2024, 1:20 p.m.

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MonikaStop

Highly Voted 8 months, 1 week ago

Selected Answer: B

DATESBETWEEN creates a continuous range of dates from the selected date back 30 days. So option B is more suitable for calculating a rolling 31-day total because it correctly defines the date range needed for the calculation.

upvoted 11 times

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Jayaruwan

Highly Voted 8 months, 2 weeks ago

Selected Answer: A

Answer A is correct because Dateadd provides required set of dates

upvoted 7 times

tko86

5 months, 1 week ago

A. CALCULATE(SUM(Sales[SalesAmount]), DATEADD(Date[Date], -30, DAY)): This is incorrect because DATEADD shifts the entire date context by 30 days. It doesn't create a range of dates. It would calculate the sales for the single day 30 days prior to the currently filtered date, not for the 31-day period.

upvoted 1 times

Odidepse

4 months, 1 week ago

DATEADD just shifts the date, but it’s not ideal for creating a rolling date range like DATESBETWEEN which can specify the exact date range for the rolling 31-day total (starting from the selected date and including the previous 30 days).

upvoted 1 times

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1CY1

8 months, 1 week ago

A is simple and I can't see whats wrong with it. -> Ans : A

upvoted 1 times

1CY1

7 months, 2 weeks ago

Changed mind... I thought A would just give you a single day 30 days earlier. -> Ans : B

upvoted 2 times

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SylUK

Most Recent 3 months, 3 weeks ago

Selected Answer: B

B is the correct answer because the question says: 'Create a DAX measure for a rolling 31 days sales total that will return the total sales amount for a SELECTED DATE ( that can be yesterday, today,27/01/2025 or tomorrow. Etc for example) and the PREVIOUS 30 DAYS' In my point of view, this question is asking us to aggregate the sales amount from the PREVIOUS 30 DAYS to the SELECTED DATE. Therefore DATEBETWEEN is the perfect function to use in this case. It can't be DATEADD function because it is a comparison function and the question is not looking for a comparison between the 2 periods ( SELECTED DATE and the PREVIOUS 30 DAYS) . The question is looking for the total sales amount for a specified period (SELECTED DATE and the PREVIOUS 30 DAYS) instead.

upvoted 1 times

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Pey1nkh

4 months, 2 weeks ago

Selected Answer: B

The DATESBETWEEN function defines a range of dates: From MAX(Date[Date]) - 30 (30 days before the selected date) To MAX(Date[Date]) (the selected date). This correctly captures all dates in the 31-day rolling window. why not Dateadd: The DATEADD function shifts the entire date context backward by 30 days. This means the calculation will consider only the values on dates exactly 30 days ago and not the entire rolling range of 31 days.

upvoted 2 times

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