How to use Views to obtain this?
Checkout the Views Group By module, this will do it. Here is a quote about it (from the module's project page):

... enriches Views2 functionality with SQL Grouping and Aggregation capabilities.
A new field group: SQL Aggregation is added, in Views, once you install the module. The field group has one available field: SQL Aggregation: Group By Fields. The field allows to configure many aspects of &quot;group by&quot; SQL clause and &quot;count()&quot; fields.