Apache Spark is a unified analytics engine for large-scale data processing. Today, you can use the built-in JDBC connector to connect to Azure SQL Database or SQL Server to read or write data from Spark jobs.
The Spark connector for Azure SQL Database and SQL Server enables SQL databases, including Azure SQL Database and SQL Server, to act as input data source or output data sink for Spark jobs. It allows you to utilize real-time transactional data in big data analytics and persist results for adhoc queries or reporting.
Read about it in the Azure blog.