SQL for Beginners

SQL for Beginners is one of Breni's learning paths, built for anyone who wants to get answers out of a database without waiting for someone else. Its 7 courses go from how relational databases are organised to filtering, aggregating, joining tables, subqueries, window functions, and creating and designing tables. Learners finish able to write queries that answer real questions and to design a small database that avoids duplicated data. Joins come only after you can filter and group, as each course opens when the last is complete.

  • 7 courses
  • 10 learning objectives
  • Level: beginner
  • Language: English
  • Price: Subscription, free trial

What you will be able to do

  • Write SELECT queries that filter, sort and limit rows from a table
  • Summarise data with COUNT, SUM, AVG, GROUP BY and HAVING
  • Combine tables with inner and left joins without duplicating rows
  • Use CTEs and window functions to rank rows and calculate running totals
  • Create, change and protect tables with constraints, indexes and transactions

Full curriculum

Part 1 · Querying

1. How Databases Work: Relational Data Basics

Explain how a relational database stores data in related tables. Units, in order: Tables, rows and columns; Primary keys; How tables relate to each other; MySQL, PostgreSQL and SQLite compared; Running your first query.

  • — Tables, Rows, and Columns
    Learn how relational databases organize data in tables, rows, and columns.
    • What is a table
    • Rows and columns
  • — Primary Keys
    Discover how primary keys give every single row a unique identity.
    • What is a primary key
    • Finding rows with keys
  • — Table Relationships
    See how separate tables connect together to store complex data.
    • Connecting tables together
    • Relational data design
  • — Popular Database Systems
    Compare MySQL, PostgreSQL, and SQLite to see their differences.
    • MySQL and PostgreSQL
    • Lightweight SQLite
  • — Your First Query
    Write and run your first simple query to read data.
    • Writing a basic query
    • Viewing query results

2. Selecting and Filtering

Pull exactly the rows and columns you need from one table. Units, in order: SELECT and choosing columns; WHERE with AND, OR and NOT; ORDER BY and LIMIT; Pattern matching with LIKE; Working with NULL.

3. Aggregating Data

Turn many rows into summary numbers grouped by category. Units, in order: COUNT, SUM, AVG, MIN and MAX; GROUP BY; Filtering groups with HAVING; DISTINCT and counting unique values; Rounding and formatting summary numbers.

Part 2 · Combining data

4. Joining Tables

Combine data spread across several tables into one result. Units, in order: Foreign keys; INNER JOIN; LEFT JOIN and missing matches; Joining three or more tables; Avoiding duplicated rows after a join.

5. Subqueries, CTEs and Window Functions

Break hard questions into steps and calculate across rows. Units, in order: Subqueries inside WHERE and FROM; Common table expressions with WITH; CASE expressions; ROW_NUMBER and RANK; Running totals and moving averages.

Part 3 · Building databases

6. Creating and Changing Tables

Create tables and safely add, change and delete data. Units, in order: CREATE TABLE and data types; Constraints: NOT NULL, UNIQUE and CHECK; INSERT, UPDATE and DELETE; ALTER TABLE to add or change columns; Transactions and rolling back mistakes.

7. Database Design and Performance

Design a small database that stays consistent and fast as it grows. Units, in order: Normalisation and avoiding repeated data; Modelling one-to-many and many-to-many relationships; Indexes and when they help; Reading a query plan; SQL injection and parameterised queries.

Sample: How Databases Work: Relational Data Basics

The opening tier, (Tables, Rows, and Columns). Learn how relational databases organize data in tables, rows, and columns.

What is a table

Understand how data lives inside a database table.

Rows and columns

Learn what rows and columns mean in a table.

Questions about SQL for Beginners

How long does it take to learn SQL?

The core of SQL is small, so regular practice gets you writing useful queries fairly quickly. On Breni each lesson takes about three minutes and the 7 courses are self-paced.

Is SQL hard to learn for beginners?

SQL is one of the easier languages to start with because queries read close to English. The path begins with how tables work before any query is written.

Which SQL does this path teach: MySQL or PostgreSQL?

It teaches standard SQL that works across MySQL, PostgreSQL and SQLite, and points out the few places where they differ.

Do I need SQL for data analysis?

For most analyst work, yes, because company data usually lives in databases. The Data Analysis for Beginners path on Breni shows SQL used alongside spreadsheets and dashboards.

Do I get a certificate for learning SQL?

Yes. Completing all 7 courses earns a certificate of completion, which is a record of finishing the path rather than a professional credential.

Related learning paths

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