What is the difference between joins and relationships in Tableau?
Ever wondered what is the difference between joins and relationships in Tableau?
Join:
A join merges tables before analysis/data visualization. If you don’t know what joins are, the inquisitive learner can put out a post for that too. Do let us know in the comments section below if you need an easy to understand post on Joins. For now, understand that like SQL, in tableau too, there are 4 kinds of joins – Left Outer Join, Right Outer Join, Inner Join and Full Outer Join (aka Outer Join). The image below shows inner join.
This creates a fixed output joined table on which further analysis/visualization can take place.
Relationships:
Relationships are links between different tables that do not form a final table as seen in case of joined table or Join Operation result. Relationships maintain separate tables while still being able to combine during analysis/ data visualization defined by business logic. Only those items are pulled during analysis that are needed (see light pink and dark pink cells that have been pulled in the image).
Thus, in case of relationships, tableau queries only the data needed to create the visualization. This saves time and performance.
