MS SQL Version, Instance and Compatibility Level, Installed Date

How to get/know the MS SQL Version?

SELECT @@VERSION;

How to get/know the MS SQL Instance?

SELECT @@SERVERNAME;

How to get/know the MS SQL Compatibility Level?

SELECT compatibility_level FROM sys.databases WHERE name = 'YourDatabaseName'; 

How to change the MS SQL Compatibility Level?

ALTER DATABASE YourDatabaseName

SET COMPATIBILITY_LEVEL = 120;

   -- COMPATIBILITY_LEVEL = { 150 | 140 | 130 | 120 | 110 | 100 | 90 } 

How to get/know the MS SQL Installed Date?

SELECT create_date AS InstalledDateTime

FROM sys.server_principals

WHERE sid = 0x010100000000000512000000

How to get/know the latest upgrade date of MS SQL Server? 

• Go to Control Panel\All Control Panel Items\Programs and Features, locate "Microsoft SQL Server" , the 'installed on' field will show you the date when it was been installed