9.2. One Chart, One Data Source
The fundamental concept in Looker Studio is that one chart can only connect to a single data source. This rule still holds true even when working with data blending.
Data Blending to the Rescue
Data blending comes to the rescue by allowing you to merge multiple data sources into a single blended data source. For example, if you want to add five data sources to a chart from five different accounts, you can blend those five data sources into one. Now you have a single data source that combines them all, which you can connect to a single chart.
Data Blending Types
Initially, Looker Studio's data blending feature only supported the "left outer join" method, a concept borrowed from SQL. While left outer join proved to be useful in most use cases, there were still scenarios where it couldn't help.
Fortunately, Looker Studio has since added support for more join types, including full outer join, right join, inner join, and cross join. These join types offer more flexibility when blending data from different sources.
For the purpose of this lesson, we'll focus on the foundations of data blending using the left join method. Once you understand the basics, you'll be able to apply the same principles to the other join types in Looker Studio.
To learn more about different join types, you can search for articles or videos about SQL joins, as the concepts are similar.