Learning SQL
by Alan Beaulieu
Master the fundamentals of SQL and relational databases. This guide covers everything from basic queries to advanced joins, subqueries, and database design principles.
Last updated: 2026-02-05
Chapters
This guide covers the following chapters. Work through them in order for the best learning experience.
Introduction to Databases
Understanding databases, SQL history, and relational model fundamentals
Creating and Populating a Database
Setting up tables, data types, and inserting your first data
Query Primer
The SELECT statement, column selection, and basic query structure
Filtering Data
WHERE clauses, comparison operators, and logical conditions
Querying Multiple Tables
Understanding joins and combining data from related tables
Working with Sets
UNION, INTERSECT, EXCEPT and set theory in SQL
Data Generation and Conversion
String functions, date handling, and type conversion
Grouping and Aggregates
GROUP BY, aggregate functions, and HAVING clauses
Subqueries
Nested queries, correlated subqueries, and derived tables
Joins Revisited
Advanced join techniques, self-joins, and outer joins
Conditional Logic
CASE expressions, COALESCE, and conditional data handling
Transactions
ACID properties, transaction control, and data integrity
Indexes and Constraints
Performance optimization and data integrity enforcement
Views
Virtual tables, query simplification, and data abstraction
Metadata
Information schema, system catalogs, and database introspection