Joining tables and blending data sources are two different ways to link related data together in Tableau. Joins are performed to link tables of data together on a row-by-row basis. Blends are performed to link together multiple data sources at an aggregate level.
Joins and blends
Joining tables
Most databases have multiple tables of data that are related in some way. Additionally, with Tableau 10 and later, you are able to join together tables of data across various data connections for many different data sources. As we'll see, Tableau makes it very easy to join together tables of data relatively easy.
Consider, for example, tables such as these:
The primary table is the Hospital Visit table, which has a record for...