According to Tableau, Data blending is the ability to bring data from multiple data sources into one Tableau view, without the need for any special coding.
You can use data blending in Tableau in the following cases:
Filter on secondary dimension fields
Use secondary dimensions in the view
Link data between two data sources using fields that are not in the view
If you are combining data from the same data source, such as Excel worksheets or tables in an Oracle database, you use joining.
