Azure SQL provides multiple application-specific features that cater to the different requirements of OLTP systems:

• Columnar store: This feature allows the storage of data in a columnar format rather than in a row format.
• In-memory OLTP: Generally, the data is stored in backend files in SQL and data is pulled from them whenever it is needed by the application. Contrary to this, in-memory OLTP puts all data in memory and there is no latency in reading the storage for data. Storing in-memory OLTP data on SSD provides the best possible performance for Azure SQL.
• All features of on-premises SQL Server.