Tableau Prep Joins
Tableau Prep is preferable to Tableau Desktop when creating combined data sources as it is generally better for creating data sources. If any additional data cleaning or transformation needs to occur before or after a join, then Tableau Prep is better. Tableau Prep also offers more flexibility in the join methodology/output.
In general, Tableau Prep works the same way as Tableau Desktop when it comes to a join where two tables/data sources are being combined – one from the left and one from the right. A join clause needs to be created, and the functionality is the same again, with the ability to select fields from either side and have them be compared to see whether they are equal, not equal, greater than, less than, greater than or equal to, or less than or equal to each other. Join clauses do not include Tableau calculations in Tableau Prep but a Calculated field can be made in a clean step prior to the join step.
When it comes to the output of the...
