A calculation view is used to define more advanced slices on the data in SAP HANA database. Calculation views can be simple and mirror the functionality found in both attribute views and analytic views. However, they are typically used when the business use case requires advanced logic that is not covered in the previous types of information views.
For example, calculation views can have layers of calculation logic, can include measures sourced from multiple source tables, can include advanced SQL logic, and so on. The data foundation of the calculation view can include any combination of tables, column views, attribute views and analytic views. You can create joins, unions, projections, and aggregation levels on the sources.
Calculation views can include measures and be used for multi-dimensional reporting or can contain no measures and used for list-type of reporting. Calculation views can either be created using a graphical editor or using a SQL Console . These various options provide maximum flexibility for the most complex and comprehensive business requirements.
You can find more details in hana developer guide
http://help.sap.com/hana/SAP_HANA_Developer_Guide_en.pdf
Hope it helps.
Regards,
Ashik