Post applies to:
SQL Server	Azure SQL VM	SQL DB Singleton	SQL DB Managed Instance	Synapse (SQL DW)

To my mind there are 3 “base” flavours of SQL Server in Azure according to their SQL Server capabilities:

• Virtual Machine SQL Server
• Azure SQL Database Singleton
• Azure SQL Database Managed Instance

For a summary of the variations on these base complexions check out my post on the exotic flavours.

Virtual Machine SQL Server

This is a full-stack SQL Server installation running on a Windows or Linux server in Azure. It has identical SQL Server capabilities to what you’re used to including the ability run SSIS, SSAS (Multi-dimensional & Tabular), SSRS, DMS and DQS.

Azure SQL Database Singleton

If you’ve never used an Azure SQL Database Singleton then you’re probably in for a bit of a shock. It’s a very different beast to what you’re used to until you remember that SQL Server is much more that an RDBMS engine – it’s a collection of data management tools & capabilities including a scheduling engine, stored connection objects, external table connectors, replication and HA capabilities. Take out these bolt-on’s and strip it back to the bare TSQL database engine and that’s what you get with a Singleton DB.

Azure SQL Database Managed Instance

Managed Instance is a full PaaS database service that looks & feels much more like the traditional SQL Server instance we’re all used to. It packs a lot of the extra-DB capabilities we’d expect to see such as SQL Agent, Replication, Linked Servers (albeit only SQL Server & Azure SQL Database endpoints are currently supported) and Management objects. It has near feature parity with a full-blown SQL Server RDBMS installation.

A picture paints a thousands words

Perhaps the difference between the 3 base flavours is best illustrated by seeing what each looks like when connected to in Management Studio.