A view is a 'virtual table' containing fields from one or more tables.
Selection views are a collection of fields from different database tables. You can create them in the Repository Browser or the Logical Database Builder in the ABAP Workbench. A virtual table that does not contain any data, but instead provides an application-oriented view of one or more ABAP Dictionary tables.
You can define joins between database tables statically and system wide as views in the ABAP Dictionary. ABAP Dictionary views can be used by all ABAP programs. One of their advantages is that fields that are common to both tables (join fields) are only transferred once from the database to the application server.
Views in the ABAP Dictionary are implemented as inner joins. If the inner table contains no lines that correspond to lines in the outer table, no data is transferred. This is not always the desired result. For example, when you read data from a text table, you want to include lines in the selection even if the corresponding text does not exist in the required language. If you want to include all of the data from the outer table, you can program a left outer join in ABAP.