The following screenshot shows a simple example of data blending in action:
There are two data source connections defined in this workbook, one for the Superstore data and the other for Superstore Sales Goals. The Superstore data source is the primary data source in this view (indicated by the blue checkmark) and Superstore Sales Goals is the secondary source (indicated by the orange checkmark). Active fields in the view that are from the secondary data source are also indicated with an orange checkmark icon.
The Sales measure has been used from the primary source and the Goals from the secondary sources. In both cases, the value is aggregated. The State dimension is an active linking field, indicated by the orange chain link icon next to the field in the data pane. Both measures are being aggregated at the level of State (sales by state in Superstore Sales, and goals by state in Superstore Sales Goals) and then matched by Tableau based on the value of the linking field State.
An examination of the data reveals that the State value in Superstore Sales is District of Columbia, while it is DC in the Superstore Sales Goals data source. You'll either need to fix the values in the data source, create a calculated field to change values, or change the alias of the value in one data source to match the value in another. For example, you could right-click District of Columbia in the row header, select Edit alias... and set the value to DC.
We'll see some examples of editing aliases throughout the book. Take note of the following definition: