There are two ways in tableau BI Services by which we can connect two data sources.
- 1. Joins: SQL joins that we use normally in Databases
- 2. Data Blending: The concept of creating relationships between data sources but at worksheet level
Most of the things that you need can be done by either Joins or Blending in Tableau.
The question that arises in mind is why do I use blending if I can use join? Which scenarios make it more suitable to use blending? Let’s tackle it one by one.
- 1. When there is no option for you to do a join your data source. For an instance: If the data sources don’t support cross database joins, and we have to use both the data source in the visualizations. Now you can use blending to achieve goals.
- 2. When there is a minor requirement for you to connect two data sources and you don’t want to use join as it the data size is large.
- 3. When your both data sources are having different level of aggregations. Like one data source is at Country level and other at city level.