hello-sql

Hello SQL is a free, beginner-level course that teaches the fundamentals of SQL and relational databases from scratch. SQL is the language used to store, retrieve, and manage data in most databases. The course is in Spanish and accompanies a 7-hour video on YouTube, originally recorded live on Twitch.

The repository contains the SQL code files that go along with over 80 video lessons covering more than 50 SQL commands. The lessons are organized into sections that follow a logical learning path: reading data, writing data, managing databases and tables, relationships between tables, joining related tables, and advanced topics.

The early lessons cover the basics of querying a database with SELECT and filtering results using commands like WHERE, ORDER BY, LIKE, and LIMIT. Later lessons move into writing data with INSERT, UPDATE, and DELETE, then into creating and modifying table structures. The section on table relationships explains the three main types of how database tables can relate to each other: one-to-one, one-to-many, and many-to-many.

The advanced section covers topics like indexes, which speed up data lookups; triggers, which run automatically when data changes; views, which save queries as reusable named objects; stored procedures, which store complex logic inside the database; and transactions, which group multiple operations so they either all succeed or all fail together.

The final section of the course shows how to connect to a database from application code, with examples in Python. Each lesson in the README links directly to the corresponding timestamp in the YouTube video and to the matching SQL file in the repository, so you can follow along in whichever order you prefer.