Welcome. SimplifyDatabase explains SQL and databases in plain English, with real examples from real systems. There’s no single right order for everyone, so pick the description that sounds most like you and follow that path.
I’m completely new to databases
Start at the top and work down. Each article builds on the one before it, and you don’t need any technical background.
- What is a Database? Explained Simply (Complete Beginner’s Guide)
- Types of Databases Explained for Beginners (With Real-Life Examples)
- SQL for Complete Beginners — Your First Queries Explained Simply
- SQL WHERE, ORDER BY & LIMIT Explained Simply (With Examples)
- SQL JOINs Explained Simply — Connecting Tables for Beginners
- SQL GROUP BY & Aggregate Functions Explained Simply
- SQL vs Excel — What’s the Difference? (And Which One Should You Learn?) (useful if you live in spreadsheets)
I know the basics and want to get better
You can write a SELECT and a JOIN. These are the topics that separate everyday SQL from really good SQL.
- SQL INSERT, UPDATE and DELETE Explained Simply
- The SQL CASE Expression Explained Simply (With Examples)
- NULL in SQL Explained Simply: IS NULL, COALESCE and Common Traps
- SQL Subqueries vs. CTEs Explained Simply (With Examples)
- SQL Window Functions Explained Simply (ROW_NUMBER, RANK, LAG and More)
- SQL Views Explained Simply: What They Are and Why to Use Them
I work with SQL Server
Practical guides for people using Microsoft SQL Server and SQL Server Management Studio day to day.
- Microsoft SQL Server Explained for Beginners
- SQL Stored Procedures Explained Simply (SQL Server, MySQL and PostgreSQL)
- SQL Transactions and ACID Explained Simply (With a Bank Example)
- SQL Indexes Explained Simply: What They Are and When to Use Them
- SQL Triggers Explained Simply (With a Price History Example)
- Database Backup and Restore Explained Simply (SQL Server, MySQL and PostgreSQL)
I’m a Delphi developer
Delphi and SQL Server together are still running a lot of business software. These articles include Delphi (FireDAC and ADO) examples.
My queries are slow
Start with indexes, because they fix most slow queries, then work through the rest.
I’m designing a database
Get the structure right before you write a single query. It saves months of clean-up later.
- Primary Keys vs. Foreign Keys Explained for Beginners
- Database Normalization Explained Simply: 1NF, 2NF and 3NF With Examples
- SQL Data Types Explained Simply: Choosing the Right Type for Each Column
- SQL Constraints Explained Simply: NOT NULL, UNIQUE, CHECK and DEFAULT
- SQL Transactions and ACID Explained Simply (With a Bank Example)
I’m choosing a database
Not sure whether you need MySQL, PostgreSQL, SQL Server or something else? Read these in order.
- What is a Database Server? Explained Simply for Beginners
- How to Choose the Right Database Server for Your Project
- MySQL Explained for Beginners — What It Is and How It Works
- PostgreSQL Explained for Beginners — What Makes It Different?
- MySQL vs PostgreSQL — Which Should You Use?
- SQL vs. NoSQL: Choosing the Right Database for Your Project
I’m curious about big data
What changes when data gets too big, too fast or too varied for one ordinary database.
How to Get the Most Out of This Site
- Type the examples yourself. Reading SQL is not the same as writing it. Install a free database (SQL Server Express, MySQL or PostgreSQL) and run every query.
- One article at a time. Finish a topic and practise it before moving on.
- Want a book alongside? See the best SQL and database books, grouped by level.
- Stuck or found a mistake? Get in touch. Reader questions often become new articles.
Prefer to browse? Every article is listed on the All Articles page.