SQL Server Documentation

What it is

The SQL Server technical documentation on Microsoft Learn covers SQL Server and the related Azure SQL products. As of 2026-09 the current release is SQL Server 2025 (source: Microsoft Learn). The documentation includes what's new pages, installation guides for Windows, Linux and containers, quickstarts for connecting and querying with SSMS and VS Code, the full Transact-SQL language reference, database design topics (tables, data types, indexes, views, collations), performance and monitoring guides, security, and high availability and disaster recovery.

Is it worth your time?

Yes, it is where you look up every T-SQL statement and function, with syntax diagrams, remarks and examples. The guides on index architecture, execution plans and transaction locking and row versioning are among the best explanations of how SQL Server works, and they are free.

Pages worth bookmarking

• The Transact-SQL reference: SELECT, the FROM clause and joins, OVER, MERGE, the date and time functions.
• The data types list, for choosing between NVARCHAR, DATETIME2, DECIMAL and others.
• Index architecture and design guide.
• Execution plans overview and how to display an actual execution plan.
• Transaction locking and row versioning guide, including isolation levels and snapshot isolation.
• BACKUP and RESTORE statements, and the backup overview.
• The sqlcmd utility page.

Editions for learning

SQL Server 2025 has two free Developer editions, Standard Developer and Enterprise Developer, licensed for development and testing only, and a free Express edition that can be used in production with limits, including a 50 GB maximum database size (source: Microsoft Learn, editions and supported features of SQL Server 2025, as of 2026-09).

Free vs paid

The documentation is free. SQL Server itself is free in the Developer and Express editions; production use beyond Express needs a paid licence or an Azure SQL service.

How to use it well

• Use the version selector on each page so remarks match your release.
• Read the Remarks and Examples sections of reference pages, not just the syntax block.
• Follow a quickstart once end to end, such as installing in a container and connecting with sqlcmd.

Common questions

Is Azure SQL documented here too? Yes, much of the T-SQL reference applies to both, and pages note where behaviour differs.

Where are the client tools documented? SSMS has its own documentation, and the MSSQL extension for VS Code is documented under the SQL tools section.