MySQL and Microsoft SQL Server are widely used relational database management systems that serve different needs in 2026. MySQL is an open-source database best known for simplicity, broad adoption, and strong performance for common web workloads. SQL Server is a proprietary, enterprise-focused database with deep integration into the Microsoft ecosystem.
Both systems support ACID transactions, replication, and large datasets, but they differ significantly in cost, tooling, scalability patterns, and operational complexity.
Key Differences
Licensing & Cost
- MySQL is open-source under the GPL with a free Community Edition. Commercial support and enterprise editions are available but generally result in a lower total cost of ownership.
- SQL Server is a proprietary database with multiple paid editions (Standard, Enterprise). Licensing is typically per core and can become expensive at scale. A free Express edition exists but has strict limits: the database size cap was raised from 10 GB to 50 GB per database in SQL Server 2025, though CPU (1 socket / 4 cores) and buffer pool (~1.4 GB) limits remain.
Features & Ecosystem
MySQL
- Focused, lightweight feature set
- InnoDB engine for transactions and row-level locking
- JSON support and basic full-text search
- Native
VECTORdata type (introduced in MySQL 9.0, July 2024) for AI/ML workloads - Large ecosystem in web hosting and application platforms
SQL Server
- Rich built-in tooling (SQL Server Management Studio)
- Integrated BI and analytics stack (SSIS, SSAS; note: SSRS was retired in SQL Server 2025 and replaced by Power BI Report Server, which ships free with paid SQL Server 2025 editions)
- Advanced performance features such as intelligent query processing
- Strong governance and enterprise controls
Performance & Scalability
- MySQL excels at simple, read-heavy workloads and scales efficiently using replicas, but complex transactional logic may require additional tuning.
- SQL Server is optimized for enterprise-grade transactional and analytical workloads, with strong parallel execution and optimizer maturity.
Replication & High Availability
- MySQL offers asynchronous and semi-synchronous replication, as well as MySQL InnoDB Cluster (built on Group Replication, available since MySQL 5.7), which provides automated HA with automatic failover out of the box. The characterization of MySQL HA as "DIY" no longer reflects the current tooling.
- SQL Server provides advanced native HA options such as Always On Availability Groups, failover clustering, and log shipping.
Typical Use Cases
MySQL
- Web applications and SaaS products
- CMS platforms
- Teams prioritizing simplicity and cost efficiency
SQL Server
- Enterprise OLTP systems
- Business intelligence and reporting
- Organizations invested in the Microsoft ecosystem
Side-by-Side Comparison
| Aspect | MySQL | SQL Server |
|---|---|---|
| License | Open-source (GPL) | Proprietary |
| Cost | Low / Free community | High at scale |
| Tooling | Lightweight | Rich, enterprise-grade |
| Performance | Excellent for simple queries | Strong for complex workloads |
| Replication & HA | Mature but simpler | Advanced, built-in |
| Ecosystem | Broad web ecosystem | Microsoft-centric |
| Best Fit | Web and OLTP apps | Enterprise & BI |
Final Thoughts
- Choose MySQL if you want a cost-effective, easy-to-operate database for web and transactional workloads.
- Choose SQL Server if you need a full enterprise database platform with integrated tooling, strong governance, and advanced availability features.
