Sometimes you may have data in two separate data sources that you want to analyze together on a single worksheet. While you can analyze several data sources together on the same worksheet, each worksheet must have a primary data source.
The primary data source is the connection that you first use in the view. After you drag fields to the view, the primary connection is marked with a blue check mark.
If you switch to another connection, you’ll notice that the Data window is marked with an orange color to indicate that if you use fields from this connection, it will become the secondary connection.
Multidimensional data sources (cubes) cannot be used as the secondary data source. They can only be used as the primary data source.
To add a secondary connection:
Connect to the primary data source and build a view.
When you need additional data from a separate data source, select Data > Connect to Data.
Follow the steps in How to Connect to a Data Source to connect to the secondary data source.
On the worksheet where you need the secondary data, select the new connection. Notice that the Data window is colored orange to indicate that it is a secondary data source.If your view uses any fields that exist in the secondary data source, you’ll see that Tableau automatically defined a relationship to link those two columns. Linked fields are marked with a link icon in the Data window. You can also define your own custom relationships to handle columns that don’t have matching names. You must have a linked field in the view to use data from the secondary connection.
Drag the fields from the secondary data source into the view.The fields in the view that are from the secondary data source are marked with an orange check mark to indicate that they are from the secondary data source.
To remove a secondary connection:
Right-click the secondary connection at the top of the Data window and select Close.