You need to license all physical processors in order to run instances of SQL Server 2008 R2 Datacenter in an unlimited number of virtual OSEs. In this case, you will need four Datacenter licenses.

There is a four-core minimum per virtual machine. As an alternative, organizations using the Business Intelligence or Standard Edition of SQL Server 2014 can use the Server + CAL licensing model, ...

The client has requirement that state MS SQL Server is required (namely for support reasons). The are looking to go with MS SQL Server 2012 Standard. So.

Microsoft rolled much of the SQL Server 2008 R2 Datacenter edition licensing rights into the SQL Server 2012 Enterprise edition, so the old Datacenter edition will disappear as a top product-line ...

The SQL Server 2012 Enterprise edition that's run for this assessment using MAP doesn't actually have to have a workload to be counted for licensing true-up purposes, he explained.

The barrier of entry here for these free SQL licenses can run about $17,500 per year for three years for 50 cores of SQL Server Standard, or $66,750 for 50 cores of SQL Server Enterprise.

To license under Microsoft SQL Server Enterprise 2012 they would license it as 40 (4×10) core licenses. (See the note about “Software Assurance Implications” below).