21. What is the difference between FIXED and INCLUDE LOD?
FIXED ignores dimensions in the view.
{ FIXED [Customer ID] : SUM([Sales]) }
INCLUDE adds dimensions to the view level.
{ INCLUDE [Customer ID] : SUM([Sales]) }
Interview Answer: Use FIXED when you need a calculation independent of the visualization.
22. What happens if a Dimension Filter and FIXED LOD are used together?
FIXED LOD ignores Dimension Filters unless the filter is added to Context.
Example:
{ FIXED [Region] : SUM([Sales]) }
If Region is filtered, FIXED may still calculate using all regions unless the filter is a Context Filter.
23. What is the difference between COUNT and COUNTD?
COUNT
COUNT([Customer ID])
Counts all records.
COUNTD
COUNTD([Customer ID])
Counts unique values.
Example:
101
101
102
COUNT = 3
COUNTD = 2
24. What is ATTR() in Tableau?
Returns a value if all rows have the same value; otherwise returns *.
ATTR([Region])
Often used in tooltips and blended data.
25. What is the difference between a Set and a Parameter?
Set
Dynamic list of members.
Top 10 Customers
Top 5 Products
Parameter
Single user input value.
Top N = 10
Sales Threshold = 10000
Interview Answer: Sets control data members, Parameters control values.
26. What is a Context Filter and why is it used?
A Context Filter executes before other filters.
Steps:
- Right-click filter.
- Add to Context.
Benefits:
- Improves performance.
- Controls filter execution order.
27. What is the difference between a Quick Filter and a Normal Filter?
Normal Filter
- Applied to worksheet.
Quick Filter
- Displayed to user on dashboard.
Example:
Region Dropdown
Year Selector
Category Multi-select
28. Explain Tableau Order of Execution.
Most commonly asked.
Extract Filter
↓
Data Source Filter
↓
Context Filter
↓
Dimension Filter
↓
Measure Filter
↓
Table Calculation Filter
Understanding this helps solve many filter-related issues.
29. What is the difference between Table Across and Table Down?
Used in Table Calculations.
Table Across
RUNNING_SUM(SUM([Sales]))
Calculates horizontally.
Table Down
RUNNING_SUM(SUM([Sales]))
Calculates vertically.
Difference is in Compute Using settings.
30. What is the difference between Inner Join and Left Join in Tableau?
Inner Join
Returns matching records only.
A INNER JOIN B
ON A.ID = B.ID
Left Join
Returns all records from left table.
A LEFT JOIN B
ON A.ID = B.ID
Interview Example:
Customer Table = 100 customers
Orders Table = 80 customers
- Inner Join → 80 customers
- Left Join → 100 customers
Senior-Level Bonus Question
Why are Relationships preferred over Joins in Tableau?
Answer:
- Relationships preserve table granularity.
- Avoid duplicate records.
- Tableau generates optimized queries automatically.
- Better for large star-schema data models.
This is a very common question in Tableau 2020.2+ interviews.
