You can enter a join condition to join multiple SAP Dynamic ABAP Table Extractor source tables.
Configure the source join from the Application Source Qualifier transformation of the parent table. When you configure the join in the Mapping Designer, retain the source qualifier only of the parent table and then link the fields from the child tables to the parent source qualifier.
Use the Platform Expression type to define the relationship of the tables that you want to join.
The following image shows the join condition for two tables using the Platform Expression type: