When licensing for a single-processor server, you must adhere to Microsoft's "Per Core" licensing model, which requires a minimum of 4 core licenses per physical processor, even if the processor has fewer than 4 cores . Core Licensing Requirements
: The "Per Core" model allows for an unlimited number of users or devices to connect to the server without needing additional Client Access Licenses (CALs) . Available SQL Server 2017 Enterprise Options
: If your single processor has more than 4 cores, you must license every physical core in that processor .
: A minimum of 4 core licenses is required for each physical processor (socket) .
While Microsoft officially uses core-based licensing for Enterprise, various retail and volume licensing options exist: Go to product viewer dialog for this item. SQL Server 2017 Enterprise 16-Core
: Core licenses are typically sold in packs of two . To meet the 4-core minimum for one processor, you would need to purchase two 2-core packs .