55 SQL Q&A in Layman’s Language with Simple Examples
Master SQL concepts easily, even if you're from a non-IT background.
Practical, real-life explanations for every question – by Rishab Informatica Group.
1. 📌 What is SQL, and Why is it Important?
+2. 🔑 What is a Primary Key, and Why is it Important?
+3. 🌉 What is a Foreign Key, and How is it Related to a Primary Key?
+4. 🔄 Describe the differences between INNER JOIN, LEFT JOIN, and RIGHT JOIN
+5. 🔄 What is a Self-Join, and When Do We Use It?
+6. 🔄 Difference Between SQL and NoSQL Databases
+7. 🧹 What is Normalization in a Database?
+8. 🚀 What is Denormalization in a Database?
+9. 🔍 What is a Subquery?
+10. 🔀 What is UNION and UNION ALL?
+11. 🚨 What is SQL Injection?
+12. 📊 What is GROUP BY?
+13. 🔄 What is a Correlated Subquery?
+14. 🔧 Explain the difference between a stored procedure and a function
+15. 🐢 Why is My SQL Query Slow?
+16. 🔍 What is an Index in a Database?
+17. 📚 What is a Clustered and Non-Clustered Index?
+18. 🔑 What's the Difference Between Candidate Key, Primary Key & Super Key?
+19. 🚨 What is a Trigger in SQL, and How is It Used?
+20. 💰 What is a Database Transaction?
+21. 🧪 Explain ACID properties in the context of SQL databases?
+22. 🔐 What's the Difference Between Primary Key and Unique Constraint?
+23. ❓ What is NULL in SQL?
+24. 🔄 What is the Purpose of the SQL CASE Statement?
+25. 👀 What is a View in SQL?
+26. 🔍 What is the EXISTS Clause?
+27. 🔢 What is the Purpose of the SQL COUNT() Function?
+28. 🔠 What's the Difference Between CHAR and VARCHAR?
+29. 🔗 JOIN vs UNION — What's the Difference?
+30. 🛠️ What is DDL and DML in SQL?
+31. ◻ What are CTEs (Common Table Expressions) in SQL?
+32. 📄 What is Data Paging in SQL?
+33. 🔁 What is a Cursor in SQL?
+34. ◻ What is TRUNCATE in SQL?
+35. 🔄 What is a Deadlock in a Database?
+36. ↔️ What is the difference between a left outer join and a right outer join?
+37. 🔄 What is ROLLBACK in SQL?
+38. 🚀 How to Make SQL Queries Faster Using Indexes
+39. 🤝 What is a natural join, and when would you use it?
+40. 🔍 Explain the differences between the CHARINDEX and PATINDEX functions.
+41. ❌ What is the DIFFERENCE BETWEEN DELETE and DROP commands in SQL?
+42. ⏹️ What is the LIMIT clause in SQL and Why Is It Useful?
+43. 🔍 What is the Difference Between WHERE and HAVING in SQL?
+44. ↔️ What is the SQL BETWEEN Operator?
+45. 🔘 What is the IN Operator in SQL?
+46. 🔄 What is an INNER JOIN, and when would you use it?
+47. 👈 What is a LEFT JOIN, and how is it different from INNER JOIN?
+48. 👉 What is a RIGHT JOIN, and how is it used?
+49. ↔️ What is a FULL OUTER JOIN, and when would you use it?
+50. ✖️ What is a CROSS JOIN, and when should you use it?
+51. 🏆 What is the difference between RANK(), DENSE_RANK(), and ROW_NUMBER()?
+52. 🔀 What is the difference between UNION and UNION ALL?
+53. 🔑 What is a surrogate key?
+54. 🧩 What is a composite key?
+55. 🔍 What is the difference between EXISTS and IN?
+Showing 55 of 55 questions