The correct answer is CALCULATE(SUM(Sales[Amount]), PREVIOUSMONTH(Date[Date])). This works because PREVIOUSMONTH is a dedicated time intelligence function that returns a contiguous set of dates for the entire prior month based on the last date in the current filter context, and when wrapped in CALCULATE, it cleanly shifts the filter on the Date dimension to that previous month. While DATEADD can also achieve the same result using DATEADD(Date[Date], -1, MONTH), PREVIOUSMONTH is more explicit and less error-prone for this specific use case. On the PL-300 exam, this distinction tests your understanding of time intelligence functions and their filter context behavior; a common trap is forgetting that PREVIOUSMONTH requires a continuous date column and an active relationship, or mistakenly using it outside CALCULATE. Remember the memory tip: “PREVIOUSMONTH gives you the full month behind, no need to count months—just wrap it in CALCULATE.”
PL-300 Model the data Practice Question
This PL-300 practice question tests your understanding of model the data. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A Power BI developer creates a star schema with a fact table Sales and dimension tables Customer, Product, Date. The relationship between Sales and Date is active. The developer wants to create a measure that calculates the total sales for the previous month relative to any selected month. Which DAX expression should the developer use?
Option D is correct because PREVIOUSMONTH(Date[Date]) returns a set of dates for the full previous month relative to the last date in the current filter context. When wrapped in CALCULATE, it shifts the filter on the Date dimension to the prior month, correctly computing total sales for the previous month regardless of the selected month.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
PREVIOUSMONTH returns the set of dates in the previous month based on the current filter context.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse PREVIOUSMONTH (which returns the entire prior month) with DATEADD (which shifts dates individually and can produce incorrect totals when the current selection is not a full month).
Detailed technical explanation
How to think about this question
PREVIOUSMONTH is a time intelligence function that internally uses the Date table’s contiguous date range to return all dates from the first to the last day of the month immediately preceding the last visible date in the current filter context. It relies on a properly marked date table with continuous dates; if the Date table has gaps, the function may return unexpected results. In real-world scenarios, this measure is often used in monthly reporting dashboards where users select a single month via a slicer and need to compare against the prior month’s performance.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Model the data — This question tests Model the data — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: CALCULATE(SUM(Sales[Amount]), PREVIOUSMONTH(Date[Date])) — Option D is correct because PREVIOUSMONTH(Date[Date]) returns a set of dates for the full previous month relative to the last date in the current filter context. When wrapped in CALCULATE, it shifts the filter on the Date dimension to the prior month, correctly computing total sales for the previous month regardless of the selected month.
What should I do if I get this PL-300 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. You have a Power BI data model with a 'Date' table that contains continuous dates from January 1, 2020, to December 31, 2025. The 'Sales' table has a relationship with the 'Date' table. You need to create a measure that calculates the total sales for the last 12 months from the current context. Which DAX function should you use?
easy
A.PREVIOUSMONTH
B.DATEADD
✓ C.DATESINPERIOD
D.SAMEPERIODLASTYEAR
Why C: Option D is correct. DATESINPERIOD allows you to specify a range of dates (e.g., last 12 months) relative to a end date. Option A is incorrect because SAMEPERIODLASTYEAR returns the same period one year ago, not the last 12 months. Option B is incorrect because DATEADD shifts dates by an interval. Option C is incorrect because PREVIOUSMONTH returns the previous month only.
Last reviewed: Jun 11, 2026
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
This PL-300 practice question is part of Courseiva's free Microsoft certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the PL-300 exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.