Data Blending in Tableau is very useful to join two data sources. For example, If you want to generate a tableau report using multiple data sources (or different data sources) then we can simply use this Tableau Data Blending technique to join those data sources.
In this article, we will show you, how to perform data blending in Tableau with an example. For this Tableau data blending demo, we are going to use the data present in Excel Worksheet and SQL Server. So, Please refer Connecting to Excel Files in Tableau and Connecting Tableau to SQL Server articles to understand the connection settings.
NOTE: In order to perform Data Blending in Tableau, We need at least one common field in both data sources. It doesn’t matter, whether it is integer or string.
Tableau Data Blending Approach 1
To demonstrate the Tableau data blending, First, we connected to Employees.xlsx workbook and added the Employee List sheet to the data region as shown below
In this example, Our requirement is to create table report with employee first name, last name, occupation, Sales and yearly income. So, we created a simple table report with Occupation, Last name, First name on Rows and Sales Amount and Yearly income on columns. Let us see the report preview.
Scenario: Suddenly, Client changed the requirements and asked us to add department and Salary Hike percentage details for every Employee. Here the real problem is, department and Salary Hike percentage data are present in the Master SQL Server database. It means, we have to combine few columns from Local Excel Sheet and few from SQL Database. This is what we call as Tableau Data Blending
To do this data blending in tableau, Please navigate to Data menu and select New Data Source option from Menu as shown below or click on the Cylinder symbol
After you select New Data Source option, below shown window will be appeared to Connect. Here, we have to connect with SQL so select Microsoft SQL Server as shown below
From the below screenshot you can observe that we selected the Department table from Tableau Database
The following screenshot will show the newly added data source (SQL) Department table
Let us add the Department name to the Rows Card. From the below screenshot you can observe that Tableau is displaying little orange tick mark at department name and also displaying the warning message.
If you read the warning message, it is a pretty straightforward message saying that there is no relation between Employees and department. Relationship is very important in Tableau data blending so, please add the relation.
In order to add a relationship, Go to data menu and select Edit Relationships.. option as shown below
Once you select Edit Relationships.. option, a new Relationships window will be opened. Following are the option available in this window.
- Primary Data Source: Data Source from which we first dragged the fields (Dimension or Measure) into report region is called as a Primary data source. Tableau will display little Blue tick mark beside this data source
- Secondary Data Source: Data Source which is not primary. Tableau will display little orange tick mark beside secondary data source
- Automatic: If there are any common Filed names in both the data sources then tableau will automatically detect the possible relationship between those two fields.
- Custom: If there are no common Filed names in the data sources, We have to select the Custom option and add the relationship between them. For now, we are selecting this option
Dept ID in Employee table and Id in Department table are the key columns we are going to use for this Tableau Data Blending on Employee and Department table as shown below.
Once you specified the relationship, tiny URL link will appear beside the Id column. From the below screenshot, when you hover on that link, Use Id as linking filed tooltip is displaying. Click the link button to enable Data blending in tableau
When you click the link button, link button colour will change to Orange colour and Our Department column is displaying data.
Remember, If there are no matching records in Department then Null values will be displayed.
Let us add Hike Rate measure to complete our client requirements.
Tableau Data Blending Approach 2
Tableau Data Blending second approach is simple and straightforward. Instead of creating custom relationships between Id and Dept ID columns, let’s give chance to the tableau intelligence
To do this, Please select and right-click on the Id column will open the context menu. Please select the Aliases.. option from the context menu as shown below
Once you selected the Aliases.. option, a new window will popped up to rename the filed. Let us change the Id Column to Dept ID
Once you click OK button, Tableau will automatically detect the relationship between Dept ID in Employee table and Dept ID in Department table. It means you don’t have to create a relationship on your own.
From the below screenshot you can observe that tiny URL link will appear beside the Dept ID column. Click the link button to enable Tableau Data Blending
Once you click on the link button, link button color will changed to Orange color as shown below.
Let us add Department Name and Hike Rate to finish the business requirement.
Remove or Edit Relationships in Tableau
In this example, we show you, how to remove relationships that we created in Tableau data blending process. First, please navigate to Data menu and select Edit Relationships.. option from Menu as shown below
Once you select Edit Relationships.. option, a new Relationships window will open. Please select the Relationship you want to remove and Click Remove button.
In this example we have only one relationship between Dept ID and Id so, we selected it and removed.
Following warning message is displayed because we are using Department Name and Hike Rate in Tableau report.
Next, One more warning message which we have seen before. Once you click OK button, Tiny URL link will be removed besides the Id column as shown below
That’s it, We successfully removed the relationship required for Tableau Data Blending