🎓 Velnov

🗄️ Study Notes

SQL

Databases from basics to window functions - 20 topics. Every topic below has its full set of practice questions written out with the correct answer and an explanation — 600 questions in all.

  1. Introduction to Databases & SQL30 questions · 9 easy, 16 medium, 5 hard
  2. SELECT Basics30 questions · 4 easy, 18 medium, 8 hard
  3. Filtering with WHERE30 questions · 3 easy, 16 medium, 11 hard
  4. Sorting & Limiting30 questions · 2 easy, 18 medium, 10 hard
  5. Operators, NULL & Patterns30 questions · 0 easy, 16 medium, 14 hard
  6. Aggregate Functions30 questions · 3 easy, 15 medium, 12 hard
  7. GROUP BY & HAVING30 questions · 1 easy, 16 medium, 13 hard
  8. Data Types30 questions · 2 easy, 17 medium, 11 hard
  9. String Functions30 questions · 3 easy, 17 medium, 10 hard
  10. Date & Time Functions30 questions · 2 easy, 17 medium, 11 hard
  11. INNER JOIN30 questions · 3 easy, 15 medium, 12 hard
  12. OUTER JOINs30 questions · 1 easy, 14 medium, 15 hard
  13. Advanced Joins30 questions · 1 easy, 14 medium, 15 hard
  14. Set Operations30 questions · 2 easy, 15 medium, 13 hard
  15. Subqueries & CTEs30 questions · 1 easy, 14 medium, 15 hard
  16. INSERT, UPDATE, DELETE30 questions · 3 easy, 13 medium, 14 hard
  17. Tables & Constraints30 questions · 2 easy, 16 medium, 12 hard
  18. Normalization & Design30 questions · 0 easy, 16 medium, 14 hard
  19. Views, Indexes & Transactions30 questions · 0 easy, 13 medium, 17 hard
  20. Window Functions & Optimization30 questions · 0 easy, 4 medium, 26 hard