Azure single SQL database is great if we don’t want to build and maintain datacenter infrastructure; management and patching overhead is completely owned by the vendor. This helps the organization and application owners concentrate on just the design-and-usage of the database.
Azure SQL Cost
This is divided into two models;
Azure SQL Deployment models
Azure SQL deployment models determine how to structure the “SQL Server” and its database;
Azure SQL Database and Azure SQL Manage instance are manage service instances.
SQL Server on Azure VMs gives you full control over the SQL Server instance.
Azure SQL Pricing models
Depending on deployment model, there are two purchasing options;
vCore based purchasing model is available for both Azure SQL and SQL Manage instance.
The DTU-based purchasing model is available for Azure SQL database.
To better understand, use Azure pricing calculator.
https://azure.microsoft.com/en-us/pricing/calculator/
Azure SQL Service Tiers
There are two service tiers used by Azure SQL, each with a different architectural model;
A general-purpose tier for common workloads
A business-critical tier for high throughput OLTP applications requiring low latency and high resilience.
A Hyperscale tier for very large OLTP systems with faster auto-scaling, backup and restore support.
Azure SQL Compute Tiers
Under Azure SQL Database deployment option, under the vCore pricing model with General purpose storage, you will see two options;
Provisioned = Azure SQL provides Azure resources that run your database with a fixed amount of compute resources for a fixed hourly price.
Serverless = The database is provisioned as a serverless component with auto-scaling compute and billing for use per second.
Azure SQL VM Cost (IaaS model)
These are dev pricing and Windows Standard, SQL Server (both included)
8 vCPUs, 32GB RAM, 64 GB Temporary storage, $0.384/hour (With standard support = 380.32/month)
Azure SQL Managed instance cost (PaaS model)
Instance = vCore-4, 20GB memory, 736/moth license included
The only difference between these two options is administration and patch management.
Managed Instances have several key features that do not exist in Azure SQL Database most notably among these are:
Cross Database Queries and Transactions;
CLR;
SQL Server Agent, and Database Mail;
Linked Servers;
Service Broker (within the instance);
Multiple Database file groups and files;
Native Azure vNet deployment; and,
Azure Active Directory Integration;
Keep in mind that Azure SQL Managed instance does not offer SQL Server integration services and Reporting Services. You would have to provision Azure Data Factory for SQL Server integration services and Power BI for reporting.
Azure VM for development seems to be cheaper than Azure managed instance by 40%. Choice is yours.