MS SQL Interview Cheat Sheet

1. What is MS SQL Server and where is it commonly used?

Entry Full Answer →

2. Explain Database, Table, Row, and Column in relational terms.

Entry Full Answer →

3. What is a Primary Key and why is it important?

Entry Full Answer →

4. What is a Foreign Key and what problem does it solve?

Entry Full Answer →

5. What are Constraints in MS SQL?

Entry Full Answer →

6. What is Normalization and why do we use it?

Entry Full Answer →

7. Explain 1NF, 2NF, and 3NF briefly.

Entry Full Answer →

8. What is Denormalization and when is it used?

Entry Full Answer →

9. What is an Index and why is it important?

Entry Full Answer →

10. What is the difference between Clustered and Non-Clustered Index?

Entry Full Answer →

11. What is a View and why is it used?

Entry Full Answer →

12. What is a Stored Procedure and what is it used for?

Entry Full Answer →

13. What are User-Defined Functions (UDFs)?

Entry Full Answer →

14. What is a Transaction and why is it important?

Entry Full Answer →

15. Explain ACID properties in SQL.

Entry Full Answer →

16. What is a Deadlock in SQL Server?

Entry Full Answer →

17. What is Locking in MS SQL Server?

Entry Full Answer →

18. What is a Schema in SQL?

Entry Full Answer →

19. Difference between DELETE and TRUNCATE?

Entry Full Answer →

20. What is an Execution Plan and why is it important?

Entry Full Answer →

21. What is the main purpose of indexing in SQL Server?

Entry Full Answer →

22. How does SQL Server decide between a Table Scan, Index Scan, and Index Seek?

Entry Full Answer →

23. What is a Composite Index and when is it used?

Entry Full Answer →

24. What is Bookmark Lookup and why can it cause performance problems?

Entry Full Answer →

25. What is a Covering Index and why is it powerful?

Entry Full Answer →

26. What are SQL Server Statistics and why are they essential?

Entry Full Answer →

27. How do outdated or missing statistics affect query performance?

Entry Full Answer →

28. What is Parameter Sniffing and why does it occur?

Entry Full Answer →

29. What is an Execution Plan and how does SQL Server generate it?

Entry Full Answer →

30. What is the difference between Estimated and Actual Execution Plans?

Entry Full Answer →

31. What is Cardinality Estimation and why is it important?

Entry Full Answer →

32. What are Index Fragmentation and Fill Factor?

Entry Full Answer →

33. What is the Query Optimizer and how does it work?

Entry Full Answer →

34. What is a Filtered Index and when is it beneficial?

Entry Full Answer →

35. What is a Hint and when should it be used?

Entry Full Answer →

36. What is a Hotspot in indexing terms?

Entry Full Answer →

37. What is the Role of the Query Store in SQL Server?

Entry Full Answer →

38. What is an Index Seek Predicate vs Residual Predicate?

Entry Full Answer →

39. Why does SQL Server choose a Hash Match instead of Nested Loop or Merge Join?

Entry Full Answer →

40. Explain the internal structure of a SQL Server index (Clustered vs Non-Clustered). How does it affect performance?

Junior Full Answer →

41. What is an Index Seek vs Index Scan vs Table Scan? When is each used?

Junior Full Answer →

42. How does SQL Server choose an Execution Plan?

Junior Full Answer →

43. What are Statistics? Why do bad statistics slow queries?

Junior Full Answer →

44. What is a Covering Index and when should you create one?

Junior Full Answer →

45. What is a Key Lookup? Why is it expensive?

Junior Full Answer →

46. Explain Lock Escalation in SQL Server.

Junior Full Answer →

47. What is Page Splitting? How does Fill Factor help?

Junior Full Answer →

48. Explain SQL Server Memory Architecture (Buffer Pool, Plan Cache).

Junior Full Answer →

49. What is Parameter Sniffing and how do you fix it?

Junior Full Answer →

50. When should you use a Filtered Index?

Junior Full Answer →