Introduction to join calculations

In Tableau, it is also possible to join two files based on a calculation. You would use this functionality to resolve mismatches between two data sources. The calculated join can be accessed in the drop down of each join.

See the following screenshot:

If you want to know more about calculated joins, please check the Tableau Help here: https://onlinehelp.tableau.com/current/pro/desktop/en-us/joining_tables.htm #use-calculations-to-resolve-mismatches-between-fields-in-a-join.