We can union your data to combine two or more tables by appending values (rows) from one table to another. To union your data in Tableau data source, the tables must come from the same connection.
A Union operation is primarily used to combine the contents of two or more tables. In order to perform a Union operation, the number of columns and data types of the data stored in those columns must be the same across all tables on which the Union operation is being performed. The Union operation ensures that all duplicates are removed from the resultant table. This means that if there is a record that is present across different tables, it would only be present once in the resultant table.