Introduction to SQL Server

Introduction

If you have ever worked at a company running on Windows infrastructure, used a .NET application, or built a report in Power BI, there is a very good chance a Microsoft SQL Server database was sitting quietly behind the scenes. SQL Server is one of the most widely deployed relational database systems in the enterprise world, powering everything from small business inventory systems to the transactional backbone of global banks. This course teaches you SQL Server from the ground up, starting with installation and finishing with real, production-style T-SQL.

What is SQL Server?

Microsoft SQL Server is a relational database management system (RDBMS) developed by Microsoft. Like other RDBMS products (MySQL, PostgreSQL, Oracle), it stores data in tables made of rows and columns, and it enforces relationships between those tables using keys. What sets SQL Server apart is its deep integration with the Microsoft ecosystem: Windows Server, Active Directory, .NET, Azure, and business intelligence tools like SQL Server Reporting Services (SSRS) and Power BI all connect naturally to it.

SQL Server is not just a place to store rows of data. It ships with a query optimizer, a security and permissions engine, backup and recovery tooling, a job scheduler (SQL Server Agent), and support for advanced features such as full-text search, in-memory tables, and JSON handling. For this course, you will focus on the core relational engine and the T-SQL language used to talk to it.

What is T-SQL?

SQL Server speaks a dialect of SQL called Transact-SQL, or T-SQL. T-SQL implements the standard SQL you may already know — SELECT, INSERT, UPDATE, DELETE — but adds procedural extensions on top: variables, IF/WHILE control flow, TRY/CATCH error handling, stored procedures, and functions. This means T-SQL is not just for asking questions of your data; it is a full programming language for writing logic that runs directly inside the database engine.

Throughout this course, every code example is real T-SQL that you can paste directly into SQL Server Management Studio (SSMS) and run against your own local database.

SQL Server Editions

Microsoft ships SQL Server in several editions, aimed at different budgets and workloads. You do not need to memorize every difference, but you should know the names, because they come up constantly in job postings and documentation.

A First Look at T-SQL

You do not need a running SQL Server instance yet to read this — later lessons walk through installation step by step. For now, just get a feel for what T-SQL looks like. Here is a simple query against a hypothetical Employees table.

SELECT FirstName, LastName, Department, Salary
FROM Employees
WHERE Salary >= 60000
ORDER BY Salary DESC;

If that looks familiar from other databases, that's intentional — SQL Server's SELECT syntax follows the ANSI SQL standard closely. The differences show up as you go deeper: T-SQL uses TOP instead of LIMIT, GETDATE() instead of NOW(), and IDENTITY instead of AUTO_INCREMENT. You will meet all of these in later lessons.

Common Mistakes

Best Practices

Frequently Asked Questions

Key Takeaways

Summary

You now know what SQL Server is, what T-SQL is, and which free edition to install. In the next lesson, you'll look at where SQL Server came from and how its editions evolved over more than three decades of development.