https://www.sqlbi.com/articles/from-sql-to-dax-joining-tables
The SQL language offers the following types of JOIN:

INNER JOIN
OUTER JOIN
CROSS JOIN

The result of a JOIN does not depends on the presence of a relationship in the data model. You can use any column of a table in a JOIN condition.
In DAX there are two ways you can obtain a JOIN behavior. First, you can Read More →

In Analysis Services, almost every object and workload is programmable, and often there is more than one approach to choose from. Options include writing managed code, script, or using open standards like XMLA and MSOLAP if your solution requirements preclude using the .NET framework.
What you can accomplish in code
Typical programming scenarios include server and database Read More →

https://docs.microsoft.com/fr-fr/sql/analysis-services/tutorial-tabular-1400/as-adventure-works-tutorial?view=sql-server-2017
What you learn

How to create a new tabular model project at the 1400 compatibility level in Visual Studio with SSDT.
How to import data from a relational database into a tabular model project workspace database.
How to create and manage relationships between tables in the model.
How to create calculated columns, measures, and Key Performance Indicators that help Read More →