Why table calculations compute across the view in Tableau - Business Case Study

Scenario Mode

👤 Your Role: You are a data analyst working with sales data in Tableau.

📋 Request: Your manager wants to understand why the table calculations in Tableau compute results across the entire view instead of just one column or row.

📊 Data: You have monthly sales data by region and product category. The data includes columns for Region, Product Category, Month, and Sales Amount.

🎯 Deliverable: Create a simple Tableau view showing sales by region and month, apply a table calculation (running total), and explain why the calculation computes across the view.

Sample Data

Region	Product Category	Month	Sales Amount
East	Furniture	Jan	1000
East	Furniture	Feb	1200
East	Technology	Jan	1500
West	Furniture	Jan	800
West	Technology	Feb	900
West	Technology	Jan	700
South	Furniture	Feb	1100
South	Technology	Feb	1300

1

Step 1: Create a Tableau worksheet with Rows = Region, Columns = Month, and Text = SUM(Sales Amount).

Drag Region to Rows shelf, Month to Columns shelf, and SUM(Sales Amount) to Text on Marks card.

Expected Result

A table showing total sales for each region by month.

2

Step 2: Add a table calculation to compute the running total of sales across the months.

Right-click SUM(Sales Amount) on Text, select 'Add Table Calculation', choose 'Running Total', compute using 'Table (Across)'.

Expected Result

Each cell shows the running total of sales from the first month to the current month for each region.

3

Step 3: Explain why the running total computes across the view instead of just one column or row.

Table calculations in Tableau compute based on the layout of the view and the direction specified (here 'Table Across'). They use the visible data in the view as their scope.

Expected Result

The running total sums sales values across the months in the view because the calculation is set to compute across the table horizontally.

4

Step 4: Demonstrate changing the direction of the table calculation to compute down the table.

Edit the table calculation, change 'Compute Using' to 'Table (Down)'.

Expected Result

The running total now sums sales down each column (across regions) for each month.

5

Step 5: Summarize that table calculations depend on the view layout and compute direction, which is why they compute across the view.

Table calculations use the data visible in the view and the compute direction to determine how to aggregate values.

Expected Result

Learners understand that table calculations are dynamic and depend on how the data is arranged in the view.

Final Result

Month ->  Jan    Feb
Region
East       2500   3700
West       1500   2400
South      0      2400

(Values show running total of sales across months for each region)

✓Table calculations use the data visible in the view as their scope.

✓The direction setting ('Table Across' or 'Table Down') controls how calculations aggregate data.

✓Changing the view layout or compute direction changes the calculation results.

✓This behavior explains why table calculations compute across the entire view.

Bonus Challenge

Create a table calculation that computes the percent of total sales by region across all months.

Show Hint

Use the 'Percent of Total' table calculation and set 'Compute Using' to 'Table (Down)' or 'Table (Across)' depending on desired direction.