SQL

7 topics · AI-enhanced lessons

The universal language for databases. Required for every backend developer.

🟢 Beginner

2 topics

What is SQL, RDBMS, database basics

SELECT, WHERE, ORDER BY, LIMIT, DISTINCT

🟡 Intermediate

2 topics

INNER, LEFT, RIGHT, FULL OUTER, CROSS JOIN

GROUP BY, HAVING, COUNT, SUM, AVG

🔴 Advanced

3 topics

Nested queries, WITH clause, correlated subqueries

B-tree, composite indexes, EXPLAIN

BEGIN, COMMIT, ROLLBACK, isolation levels

Beginner2 topics

Intermediate2 topics

Advanced3 topics