Combo charts (bar + line) in Tableau - Real Business Scenario

Scenario Mode

👤 Your Role: You are a sales analyst at a retail company.

📋 Request: Your manager wants a visual report showing monthly sales revenue and the number of units sold over the past year. The report should help identify trends and compare sales volume with revenue.

📊 Data: You have a dataset with monthly sales data including columns: Month, Sales Revenue, and Units Sold.

🎯 Deliverable: Create a combo chart in Tableau with bars representing Sales Revenue and a line representing Units Sold, both plotted over the months.

Sample Data

Month	Sales Revenue	Units Sold
Jan	12000	300
Feb	15000	350
Mar	13000	320
Apr	17000	400
May	16000	380
Jun	18000	420
Jul	20000	450
Aug	19000	430
Sep	21000	460
Oct	22000	480
Nov	23000	500
Dec	25000	520

1

Step 1: Connect your Tableau workbook to the sales data source containing Month, Sales Revenue, and Units Sold.

No formula needed; just connect the data source.

Expected Result

Tableau data source is connected and data is loaded.

2

Step 2: Drag the 'Month' field to the Columns shelf to set the horizontal axis. Right-click the Month pill and select 'Sort...' to ensure chronological order (e.g., manual sort: Jan, Feb, Mar, etc.).

Columns: Month (sorted chronologically)

Expected Result

Months appear along the horizontal axis in chronological order.

3

Step 3: Drag 'Sales Revenue' to the Rows shelf to create a bar chart showing revenue by month.

Rows: SUM(Sales Revenue)

Expected Result

Vertical bars show total sales revenue for each month.

4

Step 4: Drag 'Units Sold' to the Rows shelf next to Sales Revenue to add a second measure.

Rows: SUM(Sales Revenue), SUM(Units Sold)

Expected Result

Two vertical axes appear, one for revenue and one for units sold.

5

Step 5: On the Marks card, select the second measure (Units Sold) and change its mark type from Bar to Line.

Marks for Units Sold: Change mark type to Line

Expected Result

Sales Revenue is shown as bars; Units Sold is shown as a line over the bars.

6

Step 6: Keep the axes unsynchronized since Sales Revenue and Units Sold have different scales. Right-click each axis to format if needed.

Axes: Independent (do not synchronize)

Expected Result

Dual axes with independent scales for accurate representation and comparison.

7

Step 7: Add axis titles and chart title to clearly label the combo chart.

Edit axis titles: 'Sales Revenue ($)', 'Units Sold'; Add chart title: 'Monthly Sales Revenue and Units Sold'

Expected Result

Chart is clearly labeled for easy understanding.

Final Result

Month | Jan  Feb  Mar  Apr  May  Jun  Jul  Aug  Sep  Oct  Nov  Dec
---------------------------------------------------------------
Revenue (Bar):  ████ █████ ████ ██████ █████ ██████ ███████ ██████ ███████ ████████ ████████ █████████
Units Sold (Line):  *----*----*----*----*----*----*----*----*----*----*----*----*

✓Sales revenue generally increases from January to December.

✓Units sold follow a similar upward trend, indicating consistent growth.

✓The combo chart helps compare revenue and sales volume trends together.

Bonus Challenge

Add a third measure showing profit margin as a separate line on the same combo chart.

Show Hint

Calculate profit margin as (Sales Revenue - Cost) / Sales Revenue, then add it as a new measure and set its mark type to Line with a different color.

Practice

1. What is the main purpose of a combo chart in Tableau?

easy

A. To filter data based on categories

B. To create a pie chart with multiple slices

C. To show only one measure as a bar chart

D. To display two different types of data using bars and lines together

Solution

1. Step 1: Understand combo chart definition

   A combo chart combines two chart types, usually bars and lines, to show different data types together.

2. Step 2: Identify the purpose in Tableau

   In Tableau, combo charts help compare two measures visually by using bars for one and lines for another.

3. Final Answer:

   To display two different types of data using bars and lines together -> Option D

4. Quick Check:

   Combo chart = bars + lines [OK]

Hint: Combo charts mix bars and lines to compare two data types [OK]

Common Mistakes:

• Thinking combo charts show only one measure
• Confusing combo charts with pie charts
• Believing combo charts filter data

2. Which step is necessary to create a combo chart in Tableau?

easy

A. Use dual axis and set different mark types for each measure

B. Create a calculated field with IF statements

C. Apply a filter to exclude null values

D. Use a single axis with one mark type

Solution

1. Step 1: Identify how to combine bars and lines

   To combine bars and lines, Tableau requires dual axes so each measure can have its own scale and mark type.

2. Step 2: Set mark types for each axis

   After dual axis, set one axis to bar marks and the other to line marks to create the combo effect.

3. Final Answer:

   Use dual axis and set different mark types for each measure -> Option A

4. Quick Check:

   Dual axis + mark types = combo chart [OK]

Hint: Dual axis + different marks = combo chart in Tableau [OK]

Common Mistakes:

• Trying to use one axis for both bars and lines
• Confusing filters or calculations with combo chart setup
• Not setting mark types separately

3. Given a combo chart with Sales as bars and Profit Ratio as a line, what happens if axes are not synchronized?

medium

A. The chart will show an error and not render

B. The line and bars may appear misaligned, confusing interpretation

C. The bars will disappear but the line remains

D. The line will convert to bars automatically

Solution

1. Step 1: Understand axis synchronization

   When axes are not synchronized, the scales differ, causing bars and lines to not align properly.

2. Step 2: Effect on visualization

   This misalignment makes it hard to compare values visually, confusing the viewer.

3. Final Answer:

   The line and bars may appear misaligned, confusing interpretation -> Option B

4. Quick Check:

   Unsynced axes = misaligned chart [OK]

Hint: Always sync axes to align bars and lines clearly [OK]

Common Mistakes:

• Expecting an error instead of misalignment
• Thinking bars or lines disappear
• Assuming automatic mark type changes

4. You created a combo chart but the line chart is not visible. What is the most likely cause?

medium

A. The second axis is not added or dual axis is not enabled

B. The data source has no values for the line measure

C. The bar chart is overlapping the line chart due to mark size

D. The filter excludes all data points for the bar chart

Solution

1. Step 1: Check dual axis setup

   If the line is missing, often the second axis for the line measure was not added or dual axis was not enabled.

2. Step 2: Confirm mark types and axes

   Without dual axis, Tableau cannot overlay line and bar marks properly, so the line won't show.

3. Final Answer:

   The second axis is not added or dual axis is not enabled -> Option A

4. Quick Check:

   Missing line = no dual axis [OK]

Hint: Enable dual axis to show both bars and lines [OK]

Common Mistakes:

• Assuming data is missing without checking axes
• Blaming filters for line missing
• Not verifying mark types

5. You want to create a combo chart showing monthly Sales as bars and cumulative Profit as a line. Which steps should you follow?

hard

A. Use a pie chart for Sales and a line chart for Profit on the same axis

B. Create cumulative Profit bar chart, add Sales as line on single axis, no synchronization needed

C. Create Sales bar chart, create cumulative Profit calculated field, add Profit as line on dual axis, synchronize axes

D. Create Sales and Profit as separate charts, then combine in dashboard without dual axis

Solution

1. Step 1: Prepare measures

   Create a bar chart for Sales and a calculated field for cumulative Profit to show running total.

2. Step 2: Build combo chart

   Add Sales as bars and cumulative Profit as a line on a dual axis, then synchronize axes for clear comparison.

3. Final Answer:

   Create Sales bar chart, create cumulative Profit calculated field, add Profit as line on dual axis, synchronize axes -> Option C

4. Quick Check:

   Dual axis + cumulative calc + sync axes = correct combo [OK]

Hint: Use dual axis and cumulative calc for combo charts with running totals [OK]

Common Mistakes:

• Not creating cumulative calculated field for Profit
• Skipping axis synchronization
• Using single axis for different scales