How to perform database join with PDI (Pentaho Data Integration)?

PDI allows you to connect two tables from the same database using the ‘Table Input’ technique, which solely uses SQL to complete the join.
Users, on the other hand, utilize the ‘Database Link’ step to join two tables from separate databases. In a database join, however, each input row query is executed on the target system from the main stream, resulting in decreased performance as the number of queries executed on the B grows.
Another approach to prevent the aforementioned problem is to combine rows from two distinct Table Input stages. You can utilise the SQL query with the ‘ORDER BY’ clause in the ‘Merge Join’ phase. Before applying merge join, keep in mind that the rows must be correctly sorted.