Top N filters in Tableau - Cell-by-Cell Formula Trace

Sample Data

Sales data for different fruit products.

Cell	Value
A1	Product
B1	Sales
A2	Apples
B2	100
A3	Bananas
B3	150
A4	Cherries
B4	90
A5	Dates
B5	120
A6	Elderberries
B6	80

Formula Trace

INDEX() <= 3

Step 1: Sort products by Sales descending

Step 2: Assign INDEX() to each product in sorted list

Step 3: Evaluate INDEX() <= 3 for each product

Cell Reference Map

Sort by B descending

↓

Apply INDEX() to sorted list

The filter uses the Sales column (B) to sort products and INDEX() to rank them.

Result

   A          B
1 Product    Sales
2 Bananas    150
3 Dates      120
4 Apples     100

(Only top 3 products shown after filter)

The Top N filter shows only the three products with the highest sales.

Sheet Trace Quiz - 3 Questions

What does the INDEX() function represent in this Top N filter?

A The total sales of each product

B The position of each product after sorting by sales

C The product name length

D The average sales across all products

Key Result

Top N filters use INDEX() on a sorted measure to keep only the top N rows.

Practice

1. What is the main purpose of using a Top N filter in Tableau?

easy

A. To remove all null values from the dataset

B. To sort data alphabetically

C. To display only the highest ranked data points based on a measure

D. To change the color of the chart dynamically

Solution

1. Step 1: Understand the concept of Top N filter

   A Top N filter is used to show only the top items based on a ranking measure, such as sales or profit.

2. Step 2: Identify the purpose in Tableau

   It helps focus on the most important data points by filtering out lower-ranked items.

3. Final Answer:

   To display only the highest ranked data points based on a measure -> Option C

4. Quick Check:

   Top N filter = show top ranked data [OK]

Hint: Top N filters show only the best items by rank [OK]

Common Mistakes:

• Confusing Top N filter with sorting
• Thinking it removes nulls instead of filtering by rank
• Assuming it changes visual styles only

2. Which of the following is the correct way to create a Top N filter using a calculated field in Tableau?

easy

A. SUM([Sales]) > [Top N Parameter]

B. RANK(SUM([Sales])) <= [Top N Parameter]

C. IF [Sales] = MAX([Sales]) THEN 1 ELSE 0 END

D. INDEX() = [Top N Parameter]

Solution

1. Step 1: Understand the use of RANK() function

   The RANK() function assigns a rank number to each row based on a measure like SUM([Sales]).

2. Step 2: Apply the Top N filter condition

   Filtering with RANK(SUM([Sales])) <= [Top N Parameter] keeps only the top N ranked items.

3. Final Answer:

   RANK(SUM([Sales])) <= [Top N Parameter] -> Option B

4. Quick Check:

   Use RANK() with <= Top N [OK]

Hint: Use RANK() with <= parameter for Top N filter [OK]

Common Mistakes:

• Using SUM([Sales]) > parameter instead of rank comparison
• Confusing INDEX() with RANK() for Top N
• Using equality instead of less than or equal

3. Given the following Tableau calculated field for a Top N filter:

RANK(SUM([Profit])) <= 3

What will this filter do when applied to a sales dataset?

medium

A. Show the bottom 3 products by profit

B. Show all products with profit less than or equal to 3

C. Show products ranked exactly 3 by profit

D. Show the top 3 products by profit

Solution

1. Step 1: Analyze the RANK() function usage

   RANK(SUM([Profit])) ranks products from highest to lowest profit by default.

2. Step 2: Understand the filter condition <= 3

   This condition keeps products ranked 1, 2, or 3, meaning the top 3 products by profit.

3. Final Answer:

   Show the top 3 products by profit -> Option D

4. Quick Check:

   RANK() <= 3 means top 3 items [OK]

Hint: RANK() <= 3 always shows top 3 by measure [OK]

Common Mistakes:

• Thinking it shows bottom 3 instead of top 3
• Confusing rank number with measure value
• Assuming equality means only rank 3, not 1 to 3

4. You created a Top N filter with this calculated field:

RANK(SUM([Sales])) < [Top N Parameter]

But when you set the parameter to 5, it only shows 4 items. What is the issue?

medium

A. The filter should use <= instead of < to include the 5th item

B. The parameter value must be a string, not a number

C. RANK() function does not work with parameters

D. The filter should use > instead of <

Solution

1. Step 1: Understand the filter condition < [Top N Parameter]

   The condition RANK() < 5 includes ranks 1, 2, 3, and 4 but excludes rank 5.

2. Step 2: Correct the condition to include the 5th item

   Changing the condition to RANK() <= 5 will include the item ranked 5.

3. Final Answer:

   The filter should use <= instead of < to include the 5th item -> Option A

4. Quick Check:

   Use <= to include Top N items [OK]

Hint: Use <= to include the exact Top N rank [OK]

Common Mistakes:

• Using < excludes the Nth item
• Thinking parameter type causes issue
• Believing RANK() can't use parameters

5. You want to create a dynamic Top N filter in Tableau that lets users select the number of top products to display by sales. Which combination of features should you use?

hard

A. Create a parameter for N, a calculated field using RANK(SUM([Sales])) <= N, and apply it as a filter

B. Create a filter on SUM([Sales]) > N without using parameters

C. Use INDEX() = N in a calculated field and apply as a filter

D. Sort products by sales and manually select top N in the view

Solution

1. Step 1: Use a parameter to let users select N

   Parameters allow users to input or select a value dynamically, such as the number of top products.

2. Step 2: Create a calculated field with RANK(SUM([Sales])) <= N

   This calculated field ranks products by sales and filters to keep only the top N based on the parameter.

3. Step 3: Apply the calculated field as a filter on the view

   Applying this filter dynamically updates the view based on the parameter value.

4. Final Answer:

   Create a parameter for N, a calculated field using RANK(SUM([Sales])) <= N, and apply it as a filter -> Option A

5. Quick Check:

   Parameter + RANK() filter = dynamic Top N [OK]

Hint: Combine parameter with RANK() filter for dynamic Top N [OK]

Common Mistakes:

• Not using parameters for dynamic input
• Using INDEX() which depends on view order
• Manually selecting top N instead of filtering