Tableau Exam Desktop-Specialist Topic 5 Question 57 Discussion

Joins combine tables by adding more columns of data across similar row structures. This can cause data loss or duplication if tables are at different levels of detail, and joined data sources must be fixed before analysis can begin.

Inner join

Left Join

Blends, unlike relationships or joins, never truly combine the data. Instead, blends query each data source independently, the results are aggregated to the appropriate level, then the results are presented visually together in the view.

https://help.tableau.com/current/pro/desktop/en-us/multiple_connections.htm