When you create a view, it is created on top of multiple database tables using an inner join. Note that basis table of database views should be transparent tables.
To create a view on 2 tables, you have to enter the primary table you want to maintain and place the cursor in that field and click on the button below the list of tables and select the other table to add the view. If you are not getting this option, it means Relationship is wrong.
To know more about database Views: https://help.sap.com/doc/abapdocu_750_index_htm/7.50/en-US/abenddic_database_views.htm