How to find SQL Version

How to get SQL Server Version Information

SELECT @@SERVERNAME AS [Server Name],

       @@VERSION AS [SQL Server and OS Version Info];

How to check when sql server is installed:

SELECT  @@SERVERNAME AS [Server Name],

           create_date AS [SQL Server Install Date]

FROM    sys.server_principals WITH (NOLOCK)

WHERE   name = N'NT AUTHORITY\SYSTEM'

or      name = N'NT AUTHORITY\NETWORK SERVICE' OPTION (RECOMPILE);

How to get server properties

SELECT SERVERPROPERTY('MachineName') AS [MachineName],

              SERVERPROPERTY('ServerName') AS [ServerName], 

              SERVERPROPERTY('InstanceName') AS [Instance],

              SERVERPROPERTY('IsClustered') AS [IsClustered],

              SERVERPROPERTY('ComputerNamePhysicalNetBIOS') AS [ComputerNamePhysicalNetBIOS],

              SERVERPROPERTY('Edition') AS [Edition],

              SERVERPROPERTY('ProductLevel') AS [ProductLevel],

              SERVERPROPERTY('ProductVersion') AS [ProductVersion],

              SERVERPROPERTY('ProcessID') AS [ProcessID],

              SERVERPROPERTY('Collation') AS [Collation],

              SERVERPROPERTY('IsFullTextInstalled') AS [IsFullTextInstalled],

              SERVERPROPERTY('IsIntegratedSecurityOnly') AS [IsIntegratedSecurityOnly];