Introduction
In Day 41, you learned core interview concepts like:
Measures vs Columns
CALCULATE
ALL
Filter Context
Calendar table importance
Now comes the next level.
Scenario-based interview questions.
In real interviews, companies often ask:
“What would you do if something goes wrong in a dashboard?”
Because in real projects:
Problems happen constantly.
Charts may show wrong values.
Filters may not work correctly.
YTD calculations may fail.
In Day 42, you will learn how to identify and solve common Power BI problems using your Combined_Sales and Calendar tables.
What You Will Learn Today
You will solve real Power BI problems
You will understand debugging logic
You will learn common interview scenarios
You will improve practical thinking skills
Why This Skill Matters for Your Career
Building dashboards is one skill.
Fixing broken dashboards is another.
Companies value people who can:
Identify issues
Understand why issues happen
Fix them correctly
This is what separates beginners from professionals.
Scenario Question 1
Why are slicers not affecting a visual?
Possible Reasons
No relationship between tables
Visual interactions disabled
Measure removing filters using ALL
Wrong field used in slicer
Practical Example
Suppose:
Region slicer changes charts
But KPI card does not change.
Possible reason:
Measure uses:
CALCULATE( [Total Sales], ALL(Combined_Sales))
ALL removes slicer filters.
Interview Explanation
If slicers are not affecting visuals, first check relationships, visual interactions, and whether ALL is removing filters.
Scenario Question 2
Why is YTD showing wrong values?
Possible Reasons
No Calendar table
Relationship not connected
Using text month instead of proper date
Missing continuous dates
Correct Setup
Relationship:
Calendar[Date] → Combined_Sales[Date]
Measure:
Sales YTD =TOTALYTD( [Total Sales], Calendar[Date])
Interview Explanation
Time Intelligence functions require a proper date table and relationship.
Scenario Question 3
Why is a table showing duplicate values?
Possible Reasons
Many-to-many relationship
Wrong relationship direction
Using incorrect fields
Practical Example
If Product repeats multiple times unexpectedly:
Check:
Relationships
Granularity of data
Duplicate rows in source table
Interview Explanation
Duplicate values usually occur because of incorrect relationships or duplicated source data.
Scenario Question 4
Why is dashboard performance slow?
Possible Reasons
Too many visuals
Large calculated columns
Complex DAX
Too many slicers
Importing unnecessary columns
Practical Solution
Use:
Measures instead of columns
Hide unused fields
Reduce unnecessary visuals
Interview Explanation
Optimizing model size and reducing unnecessary calculations improves performance.
Scenario Question 5
Why does Total Sales change when clicking charts?
Answer
Because visuals create filter context.
Example:
Clicking:
Region = West
filters all connected visuals.
Important Understanding
Cross-filtering is default Power BI behavior.
Interview Explanation
Visual interactions automatically apply filters between visuals unless manually changed.
Scenario Question 6
Why does a KPI card show overall sales while charts change with slicers?
Possible Reason
Measure ignores filters using ALL.
Example:
Overall Sales =CALCULATE( [Total Sales], ALL(Combined_Sales))
Charts respond to slicers.
But KPI ignores filters because ALL removes them.
Interview Explanation
ALL removes existing filter context, causing KPI to always show complete totals.
Scenario Question 7
Why is a relationship not working?
Possible Reasons
Different data types
Duplicate values on one side
Inactive relationship
Wrong columns connected
Practical Example
Calendar Date must match:
Combined_Sales Date
Both should be Date type.
Interview Explanation
Relationships work properly only when matching columns have compatible data types and correct cardinality.
Scenario Question 8
Why should measures be used in visuals instead of raw columns?
Answer
Measures:
Dynamic
Optimized
Respond correctly to filters
Raw columns:
Can create incorrect aggregations
Increase memory usage
Practical Example
Correct:
Total Sales = SUM(Combined_Sales[Sales])
Then use:
Total Sales measure in visuals.
What You Learned Today
You solved common interview scenarios related to:
Relationships
Slicers
YTD calculations
Performance issues
ALL function behavior
Cross-filtering
Measures vs raw columns
These are very common real-world Power BI interview questions.
Try This Yourself
Open your dashboard and test:
Select Region slicer
Click bar charts
Observe KPI changes
Check YTD values
Then explain:
Why visuals behave differently.
This improves debugging skills.
What Comes Next
Next, you will learn how to explain your Power BI project professionally in interviews.
Stay Connected and Keep Practicing
Blogs WhatsApp Channel (for daily quizzes and blog updates):
https://whatsapp.com/channel/0029VbCcWME4inotCWmN5511
Telegram Channel (Job Updates & Career Alerts):
https://t.me/careervalore
WhatsApp Channel (Daily Job Updates):
https://www.whatsapp.com/channel/0029Vay7sUV11ulUIhLBUI44
Conclusion
Today you learned how to think like a Power BI professional.
Not just building dashboards.
But understanding why problems happen and how to fix them.
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