What is MS SQL?

Microsoft SQL -

is a Relational Database Management System RDMS, whose task is to store and retrieve data by signal from other applications, locally and in the network. SQL Server Management Studio (SSMS) is a software package that is distributed as part of the SQL Server installation. SSMS is used to configure and manage components of SQL Server. SSMS also Script Editor and graphical tools for working with the server.  

The primary query languages are T-SQL and ANSI SQL.

There are several versions of SQL server as needed and determined by the workload you wish to work with. From the free version SQL Express, which distinguishes itself for desktop use and for small web applications, and up to datacenter editions for multiple cores.