Comparing On-Premise SQL Server with Azure SQL: What You Need to Know
Azure SQL · 4 min read
As more development teams move workloads to Azure, a common challenge emerges: how do you keep an on-premise SQL Server environment and an Azure SQL Database in sync? Whether you're in the middle of a migration, running a hybrid setup, or maintaining parallel environments for testing, the need to compare them is real and frequent.
What Makes Azure SQL Comparison Different
Azure SQL Database is largely T-SQL compatible with on-premise SQL Server, but there are differences. Some system objects, certain DMVs, and a handful of features differ between the two environments. A good comparison tool needs to understand these differences and not report them as false positives.
Connectivity is also different. Azure SQL requires authentication via SQL Server Authentication (not Windows Authentication) and connects over port 1433, which may need to be opened in your firewall.
Connecting to Azure SQL in SCT
SQL Server Comparison Tool handles Azure SQL connections the same way it handles any SQL Server connection:
- Use your Azure SQL server name (e.g.,
yourserver.database.windows.net) - Select SQL Server Authentication
- Enter your Azure SQL login credentials
- Specify the database name
Once connected, you can compare your Azure database against any on-premise instance — or compare two Azure databases — just like any other comparison.
Common Hybrid Scenarios
- Lift-and-shift validation: Confirm your migrated Azure database matches the on-premise source before cutting over
- Ongoing sync verification: Regularly check that schema changes are being applied to both environments
- Dev/test in Azure, production on-premise: Ensure your cloud dev environment stays aligned with production
Performance Considerations
Comparing against Azure SQL over the internet adds latency compared to comparing two local databases. For large databases with many objects, consider running comparisons during off-peak hours. Schema comparisons are fast; data comparisons on large tables take longer regardless of environment.