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DBMS Interview Questions
Top questions asked at FAANG & product companies
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DBMS
SQL
All Levels
Easy
Medium
Hard
DBMS Theory Questions
12 questions
Easy
Q1
What is the difference between DBMS and RDBMS?
Amazon
Microsoft
Google
+2 more
Medium
Q2
Explain ACID properties with examples.
Amazon
Google
Microsoft
+2 more
Medium
Q3
What is Normalization? Explain 1NF, 2NF, 3NF.
Oracle
IBM
Amazon
+2 more
Easy
Q4
What is the difference between DELETE, TRUNCATE, and DROP?
Microsoft
Oracle
Infosys
+2 more
Easy
Q5
What are different types of Keys in DBMS?
Amazon
Facebook
Apple
+2 more
Medium
Q6
Explain different types of Joins with examples.
Amazon
Microsoft
Google
+2 more
Medium
Q7
What is Indexing? When to use and when not to use?
Amazon
Google
Microsoft
+2 more
Hard
Q8
What is a Deadlock? How to prevent it?
Amazon
Microsoft
Oracle
+2 more
Hard
Q9
Explain Transaction Isolation Levels.
Amazon
Google
Uber
+2 more
Easy
Q10
What is a View? What are its advantages?
Microsoft
Oracle
SAP
+2 more
Medium
Q11
What is the difference between Clustered and Non-Clustered Index?
Microsoft
Amazon
Oracle
+2 more
Medium
Q12
Explain Relational Algebra operations.
Google
Amazon
Microsoft
+2 more
SQL Query Questions
12 questions
Medium
Q1
Find the second highest salary from Employee table.
Amazon
Google
Microsoft
+2 more
Easy
Q2
Write a query to find duplicate records in a table.
Amazon
Microsoft
Oracle
+2 more
Easy
Q3
Explain the difference between WHERE and HAVING.
Amazon
Microsoft
Google
+2 more
Medium
Q4
Write a query to find employees who earn more than their manager.
Amazon
Facebook
Google
+2 more
Hard
Q5
Explain Window Functions with examples.
Amazon
Google
Microsoft
+2 more
Hard
Q6
Find the top 3 highest paid employees in each department.
Amazon
Facebook
Google
+2 more
Medium
Q7
Write a query to delete duplicate rows keeping one.
Amazon
Microsoft
Oracle
+2 more
Easy
Q8
Explain the difference between UNION and UNION ALL.
Microsoft
Oracle
IBM
+2 more
Medium
Q9
Write a query to find cumulative/running total.
Amazon
Google
Uber
+2 more
Easy
Q10
Find employees who joined in the last 30 days.
Amazon
Microsoft
Infosys
+2 more
Hard
Q11
Write a query to pivot rows to columns.
Amazon
Microsoft
Google
+2 more
Hard
Q12
Find customers who placed orders in consecutive days.
Amazon
Uber
DoorDash
+2 more
🎯 Interview Tips
DBMS Theory
• Know ACID with bank transfer example
• Practice normalizing tables to 3NF
• Understand indexing trade-offs
• Explain isolation levels clearly
SQL Queries
• Master window functions (ROW_NUMBER, RANK)
• Practice without IDE - use paper
• Know multiple approaches for same problem
• Understand query execution order