How to Create a Combined Set in Tableau

Creating sets in Tableau is a simple way to group and compare specific subsets of your data, like top-spending customers or underperforming products. But to unlock deeper insights, you can create a combined set, which allows you to compare the members of two separate sets based on the conditions you define. This guide will walk you through exactly how to create and use combined sets in Tableau to answer more complex business questions.

What Exactly is a Set in Tableau?

Before diving into combined sets, let's quickly review what a basic set is. A set in Tableau is a custom field you create that holds a subset of your data based on specific conditions. Think of it as a special bucket you can put certain data points into. For example, you could create a set for all customers who made a purchase over $500 or a set of all sales that occurred in the last quarter.

There are two main types of sets:

• Dynamic Sets: The members of a dynamic set change when the underlying data changes. If you create a set for "Top 10 Customers by Sales," the members of that set will automatically update as your sales data is refreshed.
• Fixed Sets: The members of a fixed set do not change, even if the underlying data does. You might create a fixed set to analyze a specific cohort of customers from a marketing campaign last year.

Once created, a set partitions your data into two groups: IN (members that meet the set's criteria) and OUT (members that do not). This 'IN'/'OUT' binary state is what makes them so powerful for analysis and, ultimately, for combining.

Understanding Combined Sets

A combined set takes this concept a step further by merging two existing sets into a new one. This process allows you to perform more complex segmentation, revealing relationships between different groups that you couldn't see by looking at a single set alone.

When you combine two sets in Tableau, you have four options for how to merge the members, which will feel familiar to anyone who's worked with SQL joins or Venn diagrams.

Imagine you have two sets based on customer behavior:

• Set A: Customers who bought Product X.
• Set B: Customers who bought Product Y.

Here are the four ways you can combine them:

1. All Members in Both Sets (Union)

This option creates a new set that includes every unique member from both Set A and Set B. Using our example, this combined set would contain every customer who bought either Product X or Product Y (or both).

2. Shared Members in Both Sets (Intersection)

This option, also known as an inner join, creates a new set containing only the members that exist in both Set A and Set B. This is perfect for "and" questions. The result would be a list of customers who purchased both Product X and Product Y, which might signal a valuable cross-sell opportunity.

3. "Except" Options (Left & Right Joins)

The "except" options help you find members who are in one set but not the other. This is extremely useful for finding exceptions or isolating specific groups.

• Set A Except Set B (Subtract): Creates a set of members that are in Set A but not in Set B. This would give you a list of customers who bought Product X but have not yet purchased Product Y. This group is an ideal target for a new marketing campaign promoting Product Y.
• Set B Except Set A (Subtract): The inverse of the above, this shows you every member in Set B that is not in Set A — customers who bought Product Y but not Product X.

A Step-by-Step Guide to Creating a Combined Set in Tableau

Theory is great, but let's walk through a real-world example using Tableau's "Sample - Superstore" dataset. Our goal is to find our most profitable, high-volume customers by combining a set of top customers by sales with a set of top customers by order quantity.

Step 1: Create Your First Set

First, we need to create a set that contains our top customers by total sales. This set will identify customers who spend the most money with us.

1. In the Data pane, find the Customer Name dimension.
2. Right-click on Customer Name and select Create &gt, Set.
3. A "Create Set" dialog box will appear. Give your set a descriptive name, like [Set] Top Customers - Sales.
4. Switch to the Top tab within the dialog box.
5. Select By field. Configure it to find the Top 50 customers by Sum of Sales. This tells Tableau to find the 50 customers with the highest cumulative sales.
6. Click OK. You'll now see your new set in the "Sets" section at the bottom of the Data pane.

Step 2: Create Your Second Set

Next, let's create a second set to identify customers who place the most orders.

1. Repeat the process: Right-click on Customer Name in the Data pane and choose Create &gt, Set.
2. Name this set [Set] Top Customers - Quantity.
3. Go to the Top tab and select By field.
4. Configure it to find the Top 50 customers by the sum of Quantity.
5. Click OK.

Now you have two separate dynamic sets: one identifying your biggest spenders and another identifying your most frequent buyers. There may be some crossover, but using Tableau with these two sets can reveal valuable insights.

Step 3: Create the Combined Set

With our two base sets ready, we can combine them to find the customers who appear on both lists. These are our "whale" customers — they spend a lot and buy often.

1. In the Data pane, select both of your newly created sets. You can do this by holding down the Ctrl key (or Cmd on a Mac) and clicking on each set.
2. Right-click on either of the selected sets and choose Create Combined Set....
3. The "Create Combined Set" dialog box will appear. Give this new set a meaningful name, like [Set] High-Value & High-Frequency Customers.
4. You'll see your two selected sets listed. Now, choose how you want to combine them. For our goal, we want to find customers who are in both sets, so we'll select the second option: Shared members in both sets (the intersection).
5. Click OK.

Your new combined set is now ready to use under the "Sets" section!

Step 4: Using Your Combined Set for Analysis

Now that you have your combined set, you can use it just like any other field in Tableau to build visualizations.

Let's create a simple view to see these high-value, high-frequency customers.

1. Drag your new combined set, [Set] High-Value & High-Frequency Customers, onto the Filters shelf. By default, it will show only the members "IN" the set.
2. Drag the Customer Name dimension onto the Rows shelf.
3. Drag the Sales measure onto the Columns shelf.
4. Drag the Quantity measure onto the Columns shelf right next to Sales.
5. You now have a view that lists your most valuable customers, along with their total sales and the total quantity of items purchased. You can easily sort this view to see who your top performers are.

Practical Tips for Using Combined Sets

To get the most out of combined sets, keep these best practices in mind:

• Keep Names Clear and Consistent: As you create more sets, your Data pane can get cluttered. Use a consistent naming convention, like prepending [Set] or [Combo] to the name, to keep things organized and easy to find.
• Always add metadata if publishing the project: Add comments and descriptions, so everyone on your analytics and marketing team will be using the same information for more context.
• Always filter for ‘NULL’: Filtering out this data can prevent skewed and unpredictable outcomes with your data, so you get cleaner insights every time.
• Combine with Calculated Fields: You can reference sets within calculated fields to perform even more advanced logic. For instance, you could create a calculation like:
• Use sets as efficient filtering methods: Sets are quicker to process for the data server instead of just making complicated manual calculations. Use them!

Final Thoughts

Learning how to create and use combined sets in Tableau opens up a new layer of analytical depth, allowing you to move beyond simple filtering to perform sophisticated cohort and segmentation analysis. By merging different groups of data based on intersections, unions, and exceptions, you can uncover hidden patterns, identify key customer segments, and answer business questions that would be nearly impossible otherwise.

Manually creating sets and reports across tools like Tableau is powerful, but it still requires time, setup, and a good understanding of the tool's interface. Where we make this process easier at Graphed is by letting you build these precise analyses without the clicks. You can simply ask a question in plain English, like "Show me a list of my top 50 customers by sales who also made more than 10 purchases last quarter," and we instantly generate the interactive chart or report you need, pulling live data from all your sources.