Tableau’s data blending lets you join related data from multiple data sources into a single worksheet or visualization. Multiple different data sources such as databases, spreadsheets, tableau data extracts, etc. can be analyzed together as long as they share a common dimension. In the following simple example, I blend data from 2 different Excel spreadsheets.
Unemployment rate and the sale of new homes are two economic indicators. I would like to analyze both sets of data in one visualization to see how they relate. I have one spreadsheet with the monthly unemployment rates for the U.S. since 2003 that I will use as my primary data source. I have another spreadsheet with the the monthly data for seasonally adjusted annual rate of new home sales that I will use as my secondary data source.
To integrate or blend this data, I will use date (month and year) as the common dimension. If the name of the linking field matches, Tableau will automatically link the data fields. In my case, the name differs slightly in my primary and secondary data sources, so I have to define custom mapping between the fields using the Data Menu and choosing Edit Relationships.