Recommended modules
Pick a topic and learn with examples, then come back to practice.
SQL Basics (Beginner)
| SELECT, FROM, WHERE, ORDER BY | Learn |
JOIN Operations (Beginner)
| INNER, LEFT, RIGHT, FULL, CROSS | Learn |
Aggregate Functions (Intermediate)
| COUNT, SUM, AVG, GROUP BY, HAVING | Learn |
Subqueries (Intermediate)
| Nested queries, IN, EXISTS | Learn |
Set Operators (Intermediate)
| UNION, UNION ALL, INTERSECT, EXCEPT | Learn |
Conditional Expressions (Intermediate)
| CASE, COALESCE, IFNULL | Learn |
Common Table Expressions (Advanced)
| WITH, recursive CTEs | Learn |
Window Functions (Advanced)
| ROW_NUMBER, RANK, LEAD, LAG | Learn |
Use these relationships in JOINs: orders.customer_id = customers.id,
order_items.order_id = orders.id,
order_items.product_id = products.id.