What is SSAS in SQL Server?

What is a SSAS (SQL Server Analysis Services)

SQL Server Analysis Services (SSAS) enables BI (Business Intelligence) workers to work on multi-dimensional data in SQL Server which can be gathered from different kinds of resources like flat files to relational databases.

SSAS (SQL Server Analysis Services) has the ability to analyze data grouped and aggregated into different formats and views like the faces of a cube.

A SSAS application adds the value of data analysis and represents the data in the format of OLAP cubes, OLAP reporting or data mining features.
For reference document on How to Create OLAP Cubes on SSAS, please refer to related SQL tutorial.

SSAS is an other component of MS SQL Server just like SSIS and SSRS.