Course Overview

This course is designed for software engineers, database engineers, data engineers, and ML engineers who are preparing for SQL interviews. Whether you are a beginner or looking to brush up on your SQL skills, this course is for you. We will start with an introduction to SQL, covering all the basics, and then, dive into 75 carefully selected SQL interview questions. Each question comes with a detailed explanation to help you understand the concepts thoroughly.
Our goal is to make sure you feel confident and well-prepared for your SQL interviews. The questions are picked to reflect what you might face in real-world interviews. Join us to master SQL and ace your next coding interview!

Course Contents

1. Introduction

•       What is RDBMS?
•       What is SQL?

2. A Quick Review of DQL

•       Read data from table
•       WHERE Clause
•       Operators
•       Handle NULLs in SQL
•       DISTINCT Clause
•       ORDER BY Clause
•       LIMIT and OFFSET
•       GROUP BY
•       HAVING
•       Aggregate Functions

3. Order of Execution

•       Order of SQL Query Execution

4. SQL Functions

•       Number Functions
•       String Functions
•       Date Functions

5. Nested Queries

•       Nested Query
•       Nested Query vs SubQuery
•       Types of Subqueries

6. JOINS

•       Introduction
•       INNER JOIN
•       LEFT OUTER JOIN
•       RIGHT OUTER JOIN
•       FULL OUTER JOIN
•       SELF JOIN

7. SET Operations

•       What are SET operations?
•       UNION
•       INTERSECT
•       EXCEPT

8. A Quick Review of DML

•       INSERT
•       UPDATE
•       DELETE

9. A Quick Review of DDL

•       Keys in SQL
•       CREATE
•       ALTER
•       DROP
•       TRUNCATE
•       Indexes

10. Database Backup & Restore

•       Backup Database
•       Restore Database

11. Interview Problems – Easy

•       1. Major Cities
•       2. Not boring movies
•       3. Triangle Judgement
•       4. Biggest Single Number
•       5. Product Sales Analysis I
•       6. Product Sales Analysis II
•       7. Game Play Analysis I
•       8. Game Play Analysis II
•       9. Queries Quality and Percentage
•       10. Average Selling Price
•       11. Weather Type in Each Country
•       12. Students and Examinations
•       13. Ads Performance
•       14. Group Sold Products By The Date
•       15. Find Users With Valid E-Mails
•       16. Sellers With No Sales
•       17. Average Time of Process p
•       18. Find Followers Count
•       19. Ad-Free Sessions
•       20. Bikes Last Time Used
•       21. Daily User Engagement Levels
•       22. Employee Attendance Record
•       23. Library Book Loans
•       24. Customer Purchase Summary
•       25. Employee Email Verification
•       26. Unused Accounts
•       27. Patient Appointment No-Shows
•       28. Books and Authors
•       29. High School Attendance
•       30. Employee Absences
•       31. Green Product Identification (Easy)
•       32. Employee Department Exclusion (Easy)
•       33. Sales Person (Easy)
•       34. Employee Task Tracking (Easy)
•       35. Long Comments (Easy)

12. Interview Problems – Medium

•       1. Winning Candidate
•       2. Second Degree Follower
•       3. Nth Highest Salary
•       4. Game Play Analysis III
•       5. Game Play Analysis IV
•       6. Active Businesses
•       7. Product Price at a Given Date
•       8. Monthly Transactions II
•       9. Team Scores in Football Tournament
•       10. Page Recommendations
•       11. Running Total for Different Genders
•       12. Evaluate Boolean Expression
•       13. Active Users
•       14. Find Interview Candidates
•       15. Suspicious Bank Accounts
•       16. Order Fulfillment Rate (Medium)
•       17. Last Person to Fit in the Elevator (Medium)
•       18. Retail Expansion Analysis (Medium)
•       19. Employee Collaboration Networks (Medium)
•       20. Second Fastest Time in Races (Medium)

13. Interview Problems – Hard

•       1. Trips and Users
•       2. Human Traffic of Stadium
•       3. Students Report By Geography
•       4. Game Play Analysis V
•       5. Number of Transactions per Visit
•       6. Find the Quiet Students in All Exams
•       7. First and Last Call On the Same Day
•       8. Build the Equation
•       9. Longest Winning Streak
•       10. Dynamic Pivoting of a Table
•       11. Dynamic Unpivoting of a Table
•       12. Generate the Invoice
•       13. Popularity Percentage
•       14. Status of Flight Tickets
•       15. Viewers Turned Streamers

14. Test Your Knowledge

•       1. High Performing Employees (Easy)
•       2. Student Course Averages (Easy)
•       3. Library Book Checkout Percentage (Easy)
•       4. Employee Performance and Improvement Rate (Easy)
•       5. Find Popular Posts (Easy)
•       6. Main Office Assignment for Each Employee (Easy)
•       7. Rectangle Validation (Easy)
•       8. Library Book Checkouts by Date (Easy)
•       9. Same-Day Appointment Fulfillment (Medium)
•       10. Departments with High Earning Employees (Medium)
•       11. Students Who Attended All Courses (Medium)
•       12. Library Book Checkouts First Year (Medium)
•       13. Repeated Values in Sequence (Medium)
•       14. Product Price on a Specific Date (Medium)
•       15. School Top Achievers by Subject (Hard)