Data blending in Tableau is a powerful feature that allows you to combine data from different sources into a single view. This is particularly useful when you have data stored in different databases or files and need to analyze them together without the need for complex ETL (Extract, Transform, Load) processes.

• Primary Data Source: The main data source that you start with in your Tableau worksheet.
• Secondary Data Source: The additional data source(s) that you blend with the primary data source.
• Linking Fields: Common fields between the primary and secondary data sources used to blend the data.

1. Open Tableau and connect to your primary data source.
2. Add a new data source by clicking on the "Data" menu and selecting "New Data Source".
3. Connect to your secondary data source.

1. Drag a field from the primary data source to the Rows or Columns shelf.
2. Build a basic visualization using the primary data source.

1. Drag a field from the secondary data source to the view.
2. Tableau will automatically attempt to blend the data using common fields (linking fields).

1. Click on the Data menu and select Edit Relationships.
2. In the Edit Relationships dialog box, you can manually define the linking fields if Tableau did not automatically detect them correctly.

1. Use fields from both the primary and secondary data sources to create a combined visualization.
2. Ensure that the linking fields are correctly set to get accurate results.

You have sales data in an Excel file and customer demographic data in a SQL database. You want to analyze sales performance by customer age group.

1. Connect to the Primary Data Source (Sales Data)

   - Open Tableau.
   - Click on "Connect" and select "Microsoft Excel".
   - Choose the Excel file containing the sales data.
   - Drag the "Sales" sheet to the data pane.
   

2. Connect to the Secondary Data Source (Customer Data)

   - Click on "Data" in the menu and select "New Data Source".
   - Choose "Microsoft SQL Server".
   - Enter the server details and select the database containing customer data.
   - Drag the "Customers" table to the data pane.
   

3. Create a Basic Visualization with the Primary Data Source

   - Drag "Sales Amount" to the Columns shelf.
   - Drag "Customer ID" to the Rows shelf.
   

4. Blend with the Secondary Data Source

   - Drag "Age Group" from the secondary data source (Customer Data) to the Rows shelf.
   - Tableau will automatically create a link between "Customer ID" in both data sources.
   

5. Edit Relationships (if necessary)

   - Click on "Data" and select "Edit Relationships".
   - Ensure "Customer ID" is correctly linked between the two data sources.
   

6. Finalize the Visualization

   - Adjust the visualization to show sales amount by age group.
   - Add filters, colors, or other elements to enhance the visualization.
   

1. Connect to two different data sources: one containing product sales data and another containing product details.
2. Create a blended visualization showing total sales by product category.

1. Connect to the Primary Data Source (Sales Data)

   • Open Tableau.
   • Connect to the sales data source (e.g., Excel or CSV file).
   • Drag the "Sales" sheet to the data pane.

2. Connect to the Secondary Data Source (Product Details)

   • Click on "Data" and select "New Data Source".
   • Connect to the product details data source (e.g., SQL database).
   • Drag the "Products" table to the data pane.

3. Create a Basic Visualization with the Primary Data Source

   • Drag "Total Sales" to the Columns shelf.
   • Drag "Product ID" to the Rows shelf.

4. Blend with the Secondary Data Source

   • Drag "Product Category" from the secondary data source to the Rows shelf.
   • Tableau will automatically create a link between "Product ID" in both data sources.

5. Edit Relationships (if necessary)

   • Click on "Data" and select "Edit Relationships".
   • Ensure "Product ID" is correctly linked between the two data sources.

6. Finalize the Visualization

   • Adjust the visualization to show total sales by product category.
   • Add filters, colors, or other elements to enhance the visualization.

• Incorrect Linking Fields: Ensure that the linking fields are correctly defined to avoid incorrect data blending.
• Performance Issues: Blending large datasets can impact performance. Consider using extracts or optimizing your data sources.
• Data Granularity: Ensure that the data granularity matches between the primary and secondary data sources to avoid mismatched results.

Data blending in Tableau allows you to combine data from multiple sources seamlessly. By understanding the key concepts and following the steps outlined, you can create powerful blended visualizations that provide deeper insights into your data. In the next module, we will explore more advanced visualization techniques to further enhance your Tableau skills.