SQL
3 resources
C
⬡ Website
Full course
Problem sets & exercises
CS50's Introduction to Databases with SQL
Harvard's dedicated SQL course - CRUD normalisation joins indexes views and connecting SQL to Python. Real-world datasets throughout. Completely free.
I
⬡ Website
Interactive tutorial
Intro to SQL: Querying and Managing Data - Khan Academy
A gentle browser-based intro to SQL - creating tables inserting data querying and JOINs - with exercises at every step. No setup required.
S
▶ YouTube
Single video
SQL Explained in 100 Seconds
A punchy 100-second intro to SQL - tables foreign keys joins and why relational databases still run the world. Perfect first hook.