SQL Interview Questions

Master SQL with our comprehensive collection of 27 interview questions covering everything from basics to advanced concepts.

27 Questions

Curated

4 Categories

Organized

Detailed

Answers

Basic Questions

8 Questions
1

What is SQL and what are its main components?

2

What are the different types of SQL commands?

3

What is the difference between DDL, DML, DCL, and TCL?

4

What are primary keys and foreign keys?

5

What is the difference between UNION and UNION ALL?

6

What are constraints in SQL?

7

What is the difference between WHERE and HAVING?

8

What are aggregate functions in SQL?

Intermediate Questions

9 Questions
21

What are the different types of JOINs in SQL?

22

What is the difference between correlated and non-correlated subqueries?

23

What is normalization and why is it important?

24

What is the difference between RANK(), DENSE_RANK(), and ROW_NUMBER()?

25

What are indexes and why are they used?

26

What is the difference between clustered and non-clustered indexes?

27

What is a view and what are its advantages?

28

What are stored procedures and functions?

29

What are triggers and when should you use them?

Advanced Questions

6 Questions
41

What are transactions and ACID properties in SQL?

42

How do you handle NULL values in SQL?

43

What is the difference between DELETE, DROP, and TRUNCATE?

44

What are Common Table Expressions (CTEs)?

45

What are window functions and how do they work?

46

How do you optimize SQL query performance?

Performance & Best Practices

4 Questions
61

What are recursive queries and how do you implement them?

62

What are execution plans and how do you read them?

63

How do you handle deadlocks in SQL databases?

64

How do you implement database sharding?

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