๐๐ป๐๐ฒ๐ฟ๐๐ถ๐ฒ๐๐ฒ๐ฟ:
You have 2 minutes to solve this SQL query.
Find employees whose salary is higher than their manager's salary.
Assume the table structure is:
employees(employee_id, employee_name, manager_id, salary)
๐ ๐ฒ: Challenge accepted! ๐ช
SELECT
e.employee_id,
e.employee_name,
e.salary AS employee_salary,
m.employee_name AS manager_name,
m.salary AS manager_salary
FROM employees e
JOIN employees m
ON e.manager_id = m.employee_id
WHERE e.salary > m.salary;
๐ก Explanation:
This query uses a self join because both employees and managers are stored in the same table.
โข e represents the employee.
โข m represents the manager.
โข The join matches each employee with their manager using manager_id.
โข The WHERE clause filters employees whose salary is greater than their manager's salary.
This question tests your understanding of:
โ Self Joins
โ Aliases (e and m)
โ Comparing values across related rows
๐ฏ Expected Output Example
Employee Employee Salary Manager Manager Salary
John 90,000 David 80,000
Sarah 85,000 Michael 75,000
๐ Self joins are one of the most frequently asked SQL interview topics. Practice scenarios involving employees, managers, organizational hierarchies, categories, and parent-child relationships.
โค๏ธ React with โค๏ธ for more SQL interview challenges!
You have 2 minutes to solve this SQL query.
Find employees whose salary is higher than their manager's salary.
Assume the table structure is:
employees(employee_id, employee_name, manager_id, salary)
๐ ๐ฒ: Challenge accepted! ๐ช
SELECT
e.employee_id,
e.employee_name,
e.salary AS employee_salary,
m.employee_name AS manager_name,
m.salary AS manager_salary
FROM employees e
JOIN employees m
ON e.manager_id = m.employee_id
WHERE e.salary > m.salary;
๐ก Explanation:
This query uses a self join because both employees and managers are stored in the same table.
โข e represents the employee.
โข m represents the manager.
โข The join matches each employee with their manager using manager_id.
โข The WHERE clause filters employees whose salary is greater than their manager's salary.
This question tests your understanding of:
โ Self Joins
โ Aliases (e and m)
โ Comparing values across related rows
๐ฏ Expected Output Example
Employee Employee Salary Manager Manager Salary
John 90,000 David 80,000
Sarah 85,000 Michael 75,000
๐ Self joins are one of the most frequently asked SQL interview topics. Practice scenarios involving employees, managers, organizational hierarchies, categories, and parent-child relationships.
โค๏ธ React with โค๏ธ for more SQL interview challenges!
โค17
๐ ๐๐ฅ๐๐ ๐ง๐ฎ๐๐ฎ ๐๐ฎ๐๐ฎ ๐๐ป๐ฎ๐น๐๐๐ถ๐ฐ๐ ๐ฉ๐ถ๐ฟ๐๐๐ฎ๐น ๐๐ป๐๐ฒ๐ฟ๐ป๐๐ต๐ถ๐ฝ | ๐ช๐ถ๐๐ต ๐๐ฒ๐ฟ๐๐ถ๐ณ๐ถ๐ฐ๐ฎ๐๐ฒ ๐
Here's an amazing opportunity to complete the FREE Tata Data Analytics Virtual Internship and earn a certificate that you can showcase on your Resume and LinkedIn.
โ 100% FREE
โ Self-Paced & Online
โ Beginner-Friendly
โ Certificate on Completion
โ Real Business Case Studies
โ Resume & LinkedIn Boost
๐ ๐๐ป๐ฟ๐ผ๐น๐น ๐๐ผ๐ฟ ๐๐ฅ๐๐๐:
https://pdlink.in/4eybW8J
๐ Upskill Today. Build Your Portfolio. Get Career Ready!
Here's an amazing opportunity to complete the FREE Tata Data Analytics Virtual Internship and earn a certificate that you can showcase on your Resume and LinkedIn.
โ 100% FREE
โ Self-Paced & Online
โ Beginner-Friendly
โ Certificate on Completion
โ Real Business Case Studies
โ Resume & LinkedIn Boost
๐ ๐๐ป๐ฟ๐ผ๐น๐น ๐๐ผ๐ฟ ๐๐ฅ๐๐๐:
https://pdlink.in/4eybW8J
๐ Upskill Today. Build Your Portfolio. Get Career Ready!
โค9
๐๐ป๐๐ฒ๐ฟ๐๐ถ๐ฒ๐๐ฒ๐ฟ:
You have 2 minutes to solve this SQL query.
Find the top 3 highest-paid employees in each department.
๐ ๐ฒ: Challenge accepted! ๐ช
SELECT
employee_id,
employee_name,
department,
salary
FROM (
SELECT
employee_id,
employee_name,
department,
salary,
DENSE_RANK() OVER (
PARTITION BY department
ORDER BY salary DESC
) AS salary_rank
FROM employees
) ranked
WHERE salary_rank <= 3
ORDER BY department, salary DESC;
๐ก Explanation:
The query uses the DENSE_RANK() window function to rank employees based on salary within each department.
โข PARTITION BY department creates a separate ranking for every department.
โข ORDER BY salary DESC ranks the highest salary first.
โข DENSE_RANK() assigns the same rank to employees with identical salaries.
โข The outer query returns only employees with a rank of 3 or less.
This question tests your understanding of:
โ Window Functions
โ DENSE_RANK()
โ Top N per Group
โ Partitioning Data
๐ฏ Expected Output Example
Employee Department Salary Rank
John IT 95,000 1
Alice IT 95,000 1
Bob IT 90,000 2
Mike IT 85,000 3
Sarah HR 80,000 1
๐ Know when to use each ranking function:
โข ROW_NUMBER() โ No ties (unique ranking)
โข RANK() โ Leaves gaps after ties
โข DENSE_RANK() โ No gaps after ties (ideal for Top N with ties)
โค๏ธ React with โค๏ธ for more SQL interview challenges!
You have 2 minutes to solve this SQL query.
Find the top 3 highest-paid employees in each department.
๐ ๐ฒ: Challenge accepted! ๐ช
SELECT
employee_id,
employee_name,
department,
salary
FROM (
SELECT
employee_id,
employee_name,
department,
salary,
DENSE_RANK() OVER (
PARTITION BY department
ORDER BY salary DESC
) AS salary_rank
FROM employees
) ranked
WHERE salary_rank <= 3
ORDER BY department, salary DESC;
๐ก Explanation:
The query uses the DENSE_RANK() window function to rank employees based on salary within each department.
โข PARTITION BY department creates a separate ranking for every department.
โข ORDER BY salary DESC ranks the highest salary first.
โข DENSE_RANK() assigns the same rank to employees with identical salaries.
โข The outer query returns only employees with a rank of 3 or less.
This question tests your understanding of:
โ Window Functions
โ DENSE_RANK()
โ Top N per Group
โ Partitioning Data
๐ฏ Expected Output Example
Employee Department Salary Rank
John IT 95,000 1
Alice IT 95,000 1
Bob IT 90,000 2
Mike IT 85,000 3
Sarah HR 80,000 1
๐ Know when to use each ranking function:
โข ROW_NUMBER() โ No ties (unique ranking)
โข RANK() โ Leaves gaps after ties
โข DENSE_RANK() โ No gaps after ties (ideal for Top N with ties)
โค๏ธ React with โค๏ธ for more SQL interview challenges!
โค22
๐ ๐๐ฅ๐๐ ๐๐ฎ๐๐ฎ ๐๐ป๐ฎ๐น๐๐๐ถ๐ฐ๐ ๐๐ผ๐๐ฟ๐๐ฒ๐ | ๐ก๐ผ ๐๐
๐ฝ๐ฒ๐ฟ๐ถ๐ฒ๐ป๐ฐ๐ฒ ๐ก๐ฒ๐ฒ๐ฑ๐ฒ๐ฑ! ๐
Want to start a career in Data Analytics but don't know where to begin?
These 5 FREE beginner-friendly courses will help you learn the most in-demand data skills and build a strong foundation.
๐ ๐๐ป๐ฟ๐ผ๐น๐น ๐๐ผ๐ฟ ๐๐ฅ๐๐๐:
https://pdlink.in/3SOk64h
๐ Start Learning Today. Build Your Portfolio. Land Your Dream Data Job!
Want to start a career in Data Analytics but don't know where to begin?
These 5 FREE beginner-friendly courses will help you learn the most in-demand data skills and build a strong foundation.
๐ ๐๐ป๐ฟ๐ผ๐น๐น ๐๐ผ๐ฟ ๐๐ฅ๐๐๐:
https://pdlink.in/3SOk64h
๐ Start Learning Today. Build Your Portfolio. Land Your Dream Data Job!
โค1
๐๐ป๐๐ฒ๐ฟ๐๐ถ๐ฒ๐๐ฒ๐ฟ:
You have 2 minutes to solve this SQL query.
Find customers who have never placed an order.
Tables:
customers(customer_id, customer_name)
orders(order_id, customer_id, order_date)
๐ ๐ฒ: Challenge accepted! ๐ช
SELECT
c.customer_id,
c.customer_name
FROM customers c
LEFT JOIN orders o
ON c.customer_id = o.customer_id
WHERE o.customer_id IS NULL;
๐ก Explanation:
This query uses a LEFT JOIN to return all customers, whether or not they have placed an order.
โข LEFT JOIN keeps every customer in the result.
โข Customers without matching records in the orders table will have NULL values.
โข The WHERE o.customer_id IS NULL condition filters only customers who have never placed an order.
This question tests your understanding of:
โ LEFT JOIN
โ Finding missing records
โ NULL handling
๐ฏ Expected Output Example
Customer ID Customer Name
105 Alice
112 David
118 Sarah
๐ Questions about finding unmatched records are very common in interviews. Practice using:
- LEFT JOIN ... IS NULL
- NOT EXISTS
- NOT IN (carefully, because NULL values can affect results)
Among these, NOT EXISTS is often preferred for correctness and performance in many databases.
โค๏ธ React with โค๏ธ for more SQL interview challenges!
You have 2 minutes to solve this SQL query.
Find customers who have never placed an order.
Tables:
customers(customer_id, customer_name)
orders(order_id, customer_id, order_date)
๐ ๐ฒ: Challenge accepted! ๐ช
SELECT
c.customer_id,
c.customer_name
FROM customers c
LEFT JOIN orders o
ON c.customer_id = o.customer_id
WHERE o.customer_id IS NULL;
๐ก Explanation:
This query uses a LEFT JOIN to return all customers, whether or not they have placed an order.
โข LEFT JOIN keeps every customer in the result.
โข Customers without matching records in the orders table will have NULL values.
โข The WHERE o.customer_id IS NULL condition filters only customers who have never placed an order.
This question tests your understanding of:
โ LEFT JOIN
โ Finding missing records
โ NULL handling
๐ฏ Expected Output Example
Customer ID Customer Name
105 Alice
112 David
118 Sarah
๐ Questions about finding unmatched records are very common in interviews. Practice using:
- LEFT JOIN ... IS NULL
- NOT EXISTS
- NOT IN (carefully, because NULL values can affect results)
Among these, NOT EXISTS is often preferred for correctness and performance in many databases.
โค๏ธ React with โค๏ธ for more SQL interview challenges!
โค11๐ฅ1
๐ง๐๐ฆ ๐๐ฅ๐๐ ๐๐ฒ๐ฟ๐๐ถ๐ณ๐ถ๐ฐ๐ฎ๐๐ถ๐ผ๐ป ๐ข๐ป ๐๐ฎ๐๐ฎ ๐ ๐ฎ๐ป๐ฎ๐ด๐ฒ๐บ๐ฒ๐ป๐ - ๐๐ป๐ฟ๐ผ๐น๐น ๐๐ผ๐ฟ ๐๐ฅ๐๐๐
TCS iON is offering a FREE Master Data Management Course with a Certificate,
โ 100% FREE Learning
โ Certificate on Completion
โ Self-Paced Online Course
โ Beginner-Friendly Content
โ Industry-Relevant Skills
โ Resume & LinkedIn Profile Boost
๐ ๐๐ป๐ฟ๐ผ๐น๐น ๐๐ผ๐ฟ ๐๐ฅ๐๐๐:
https://pdlink.in/4jGFBw0
๐ Start Learning Today. Upskill for Free. Get Career Ready!
TCS iON is offering a FREE Master Data Management Course with a Certificate,
โ 100% FREE Learning
โ Certificate on Completion
โ Self-Paced Online Course
โ Beginner-Friendly Content
โ Industry-Relevant Skills
โ Resume & LinkedIn Profile Boost
๐ ๐๐ป๐ฟ๐ผ๐น๐น ๐๐ผ๐ฟ ๐๐ฅ๐๐๐:
https://pdlink.in/4jGFBw0
๐ Start Learning Today. Upskill for Free. Get Career Ready!
โค3๐1๐ฅฐ1
๐๐ป๐๐ฒ๐ฟ๐๐ถ๐ฒ๐๐ฒ๐ฟ:
You have 2 minutes to solve this SQL query.
Find the department with the highest average salary.
๐ ๐ฒ: Challenge accepted! ๐ช
SELECT
department,
AVG(salary) AS average_salary
FROM employees
GROUP BY department
ORDER BY average_salary DESC
LIMIT 1;
๐ก Explanation:
The query calculates the average salary for each department and returns the department with the highest average salary.
โข GROUP BY department groups employees by department
โข AVG(salary) calculates the average salary for each department
โข ORDER BY average_salary DESC sorts departments from highest to lowest average salary
โข LIMIT 1 returns only the top department
This question tests your understanding of:
โ GROUP BY
โ Aggregate Functions AVG
โ ORDER BY
โ LIMIT
๐ฏ Expected Output
Department Average_Salary
IT 88,500
๐ Bonus Handles Ties
If multiple departments share the highest average salary, use DENSE_RANK():
SELECT
department,
average_salary
FROM (
SELECT
department,
AVG(salary) AS average_salary,
DENSE_RANK() OVER (
ORDER BY AVG(salary) DESC
) AS rnk
FROM employees
GROUP BY department
) ranked
WHERE rnk = 1;
This version returns all departments tied for the highest average salary.
๐ Whenever you see questions like highest, lowest, top N, or rank, think beyond LIMIT. Ask yourself: What if there's a tie? Window functions like DENSE_RANK() often provide a more complete solution.
โค๏ธ React with โค๏ธ for more SQL interview challenges!
You have 2 minutes to solve this SQL query.
Find the department with the highest average salary.
๐ ๐ฒ: Challenge accepted! ๐ช
SELECT
department,
AVG(salary) AS average_salary
FROM employees
GROUP BY department
ORDER BY average_salary DESC
LIMIT 1;
๐ก Explanation:
The query calculates the average salary for each department and returns the department with the highest average salary.
โข GROUP BY department groups employees by department
โข AVG(salary) calculates the average salary for each department
โข ORDER BY average_salary DESC sorts departments from highest to lowest average salary
โข LIMIT 1 returns only the top department
This question tests your understanding of:
โ GROUP BY
โ Aggregate Functions AVG
โ ORDER BY
โ LIMIT
๐ฏ Expected Output
Department Average_Salary
IT 88,500
๐ Bonus Handles Ties
If multiple departments share the highest average salary, use DENSE_RANK():
SELECT
department,
average_salary
FROM (
SELECT
department,
AVG(salary) AS average_salary,
DENSE_RANK() OVER (
ORDER BY AVG(salary) DESC
) AS rnk
FROM employees
GROUP BY department
) ranked
WHERE rnk = 1;
This version returns all departments tied for the highest average salary.
๐ Whenever you see questions like highest, lowest, top N, or rank, think beyond LIMIT. Ask yourself: What if there's a tie? Window functions like DENSE_RANK() often provide a more complete solution.
โค๏ธ React with โค๏ธ for more SQL interview challenges!
โค15
๐ ๐ก๐ฉ๐๐๐๐ ๐๐ฅ๐๐ ๐๐ ๐๐ฒ๐ฟ๐๐ถ๐ณ๐ถ๐ฐ๐ฎ๐๐ถ๐ผ๐ป ๐๐ผ๐๐ฟ๐๐ฒ๐ | ๐๐ฒ๐ฎ๐ฟ๐ป ๐๐ฟ๐ผ๐บ ๐๐ ๐๐ป๐ฑ๐๐๐๐ฟ๐ ๐๐ฒ๐ฎ๐ฑ๐ฒ๐ฟ๐
Want to build cutting-edge *AI skills* from one of the world's leading AI and GPU companies?
*NVIDIA* offers *FREE AI Certification Courses* to help students, freshers, developers, and professionals
๐ ๐๐ป๐ฟ๐ผ๐น๐น ๐๐ผ๐ฟ ๐๐ฅ๐๐๐:
https://pdlinks.in/nvdia
๐ Start Learning Today. Earn Your Certificate. Build Your Future in AI!
Want to build cutting-edge *AI skills* from one of the world's leading AI and GPU companies?
*NVIDIA* offers *FREE AI Certification Courses* to help students, freshers, developers, and professionals
๐ ๐๐ป๐ฟ๐ผ๐น๐น ๐๐ผ๐ฟ ๐๐ฅ๐๐๐:
https://pdlinks.in/nvdia
๐ Start Learning Today. Earn Your Certificate. Build Your Future in AI!
โค1
๐๐ป๐๐ฒ๐ฟ๐๐ถ๐ฒ๐๐ฒ๐ฟ:
You have 2 minutes to solve this SQL query.
Find employees who earn the same salary as at least one other employee in the same department.
๐ ๐ฒ: Challenge accepted! ๐ช
SELECT
employee_id,
employee_name,
department,
salary
FROM employees
WHERE (department, salary) IN (
SELECT
department,
salary
FROM employees
GROUP BY department, salary
HAVING COUNT(*) > 1
)
ORDER BY department, salary DESC;
๐ก Explanation:
The query identifies duplicate salary values within each department.
โข The subquery groups records by department and salary.
โข **HAVING COUNT(*) > 1** finds salary values that appear more than once in the same department.
โข The outer query returns all employees whose (department, salary) matches those duplicate combinations.
This question tests your understanding of:
โ GROUP BY
โ HAVING
โ Multi-column filtering
โ Identifying duplicate records
๐ฏ Expected Output Example
Employee Department Salary
John IT 80,000
Alice IT 80,000
David HR 65,000
Sarah HR 65,000
๐ Alternative Using Window Functions
SELECT
employee_id,
employee_name,
department,
salary
FROM (
SELECT
*,
COUNT(*) OVER (
PARTITION BY department, salary
) AS salary_count
FROM employees
) t
WHERE salary_count > 1;
This approach avoids a subquery with GROUP BY and is a great way to showcase your knowledge of window functions.
๐ When interview questions ask you to find duplicates, think of these three approaches:
1. GROUP BY + HAVING
2. Window functions COUNT() OVER
3. Self Join for specific comparison scenarios
Knowing multiple solutions demonstrates strong SQL problem-solving skills.
โค๏ธ React with โค๏ธ for more SQL interview challenges!
You have 2 minutes to solve this SQL query.
Find employees who earn the same salary as at least one other employee in the same department.
๐ ๐ฒ: Challenge accepted! ๐ช
SELECT
employee_id,
employee_name,
department,
salary
FROM employees
WHERE (department, salary) IN (
SELECT
department,
salary
FROM employees
GROUP BY department, salary
HAVING COUNT(*) > 1
)
ORDER BY department, salary DESC;
๐ก Explanation:
The query identifies duplicate salary values within each department.
โข The subquery groups records by department and salary.
โข **HAVING COUNT(*) > 1** finds salary values that appear more than once in the same department.
โข The outer query returns all employees whose (department, salary) matches those duplicate combinations.
This question tests your understanding of:
โ GROUP BY
โ HAVING
โ Multi-column filtering
โ Identifying duplicate records
๐ฏ Expected Output Example
Employee Department Salary
John IT 80,000
Alice IT 80,000
David HR 65,000
Sarah HR 65,000
๐ Alternative Using Window Functions
SELECT
employee_id,
employee_name,
department,
salary
FROM (
SELECT
*,
COUNT(*) OVER (
PARTITION BY department, salary
) AS salary_count
FROM employees
) t
WHERE salary_count > 1;
This approach avoids a subquery with GROUP BY and is a great way to showcase your knowledge of window functions.
๐ When interview questions ask you to find duplicates, think of these three approaches:
1. GROUP BY + HAVING
2. Window functions COUNT() OVER
3. Self Join for specific comparison scenarios
Knowing multiple solutions demonstrates strong SQL problem-solving skills.
โค๏ธ React with โค๏ธ for more SQL interview challenges!
โค11
๐๐ป๐๐ฒ๐ฟ๐๐ถ๐ฒ๐๐ฒ๐ฟ:
You have 2 minutes to solve this SQL query.
Find the third highest salary from the employees table without using LIMIT or TOP.
๐ ๐ฒ: Challenge accepted! ๐ช
SELECT
salary
FROM (
SELECT
salary,
DENSE_RANK() OVER (ORDER BY salary DESC) AS salary_rank
FROM employees
) ranked
WHERE salary_rank = 3;
๐ก Explanation:
This query uses the DENSE_RANK() window function to rank distinct salary values in descending order.
โข ORDER BY salary DESC assigns Rank 1 to the highest salary.
โข DENSE_RANK() ensures duplicate salaries receive the same rank.
โข The outer query filters for salary_rank = 3, returning the third highest distinct salary.
๐ฏ Expected Output Example
Salary Rank
95,000 1
90,000 2
85,000 3
Output:
Third Highest Salary
85,000
๐ Alternative Solution Using a Correlated Subquery
SELECT DISTINCT salary
FROM employees e1
WHERE 2 = (
SELECT COUNT(DISTINCT salary)
FROM employees e2
WHERE e2.salary > e1.salary
);
This solution avoids window functions and is commonly asked to test your understanding of correlated subqueries.
๐ Questions involving the Nth highest or Nth lowest value are interview favorites. Be comfortable solving them using:
1. DENSE_RANK()
2. RANK()
3. Correlated Subqueries
4. Common Table Expressions (CTEs)
Being able to provide multiple approaches leaves a strong impression on interviewers.
โค๏ธ React with โค๏ธ for more interview challenges!
You have 2 minutes to solve this SQL query.
Find the third highest salary from the employees table without using LIMIT or TOP.
๐ ๐ฒ: Challenge accepted! ๐ช
SELECT
salary
FROM (
SELECT
salary,
DENSE_RANK() OVER (ORDER BY salary DESC) AS salary_rank
FROM employees
) ranked
WHERE salary_rank = 3;
๐ก Explanation:
This query uses the DENSE_RANK() window function to rank distinct salary values in descending order.
โข ORDER BY salary DESC assigns Rank 1 to the highest salary.
โข DENSE_RANK() ensures duplicate salaries receive the same rank.
โข The outer query filters for salary_rank = 3, returning the third highest distinct salary.
๐ฏ Expected Output Example
Salary Rank
95,000 1
90,000 2
85,000 3
Output:
Third Highest Salary
85,000
๐ Alternative Solution Using a Correlated Subquery
SELECT DISTINCT salary
FROM employees e1
WHERE 2 = (
SELECT COUNT(DISTINCT salary)
FROM employees e2
WHERE e2.salary > e1.salary
);
This solution avoids window functions and is commonly asked to test your understanding of correlated subqueries.
๐ Questions involving the Nth highest or Nth lowest value are interview favorites. Be comfortable solving them using:
1. DENSE_RANK()
2. RANK()
3. Correlated Subqueries
4. Common Table Expressions (CTEs)
Being able to provide multiple approaches leaves a strong impression on interviewers.
โค๏ธ React with โค๏ธ for more interview challenges!
โค17
๐๐ป๐๐ฒ๐ฟ๐๐ถ๐ฒ๐๐ฒ๐ฟ:
You have 2 minutes to solve this SQL query.
Find the employees who joined in the last 30 days.
Assume the table structure:
employees(employee_id, employee_name, department, joining_date)
๐ ๐ฒ: Challenge accepted! ๐ช
SELECT
employee_id,
employee_name,
department,
joining_date
FROM employees
WHERE joining_date >= CURRENT_DATE - INTERVAL '30 days';
๐ก Explanation:
This query filters employees whose joining date falls within the last 30 days.
โข CURRENT_DATE returns today's date.
โข INTERVAL '30 days' subtracts 30 days from the current date.
โข The WHERE clause returns employees who joined on or after that date.
This question tests your understanding of:
โ Date Functions
โ Date Arithmetic
โ Filtering Records with Dates
๐ฏ Expected Output Example
Employee Department Joining Date
John IT 2026-06-10
Sarah HR 2026-06-22
๐ Database-Specific Alternatives
MySQL
SELECT *
FROM employees
WHERE joining_date >= CURDATE() - INTERVAL 30 DAY;
SQL Server
SELECT *
FROM employees
WHERE joining_date >= DATEADD(DAY, -30, GETDATE());
Oracle
SELECT *
FROM employees
WHERE joining_date >= SYSDATE - 30;
๐ Tip for SQL Job Seekers:
Date-related SQL questions are very common. Make sure you're comfortable with:
โข Finding records from the last N days
โข Current month/year filters
โข Date differences
โข Date formatting
โข Database-specific date functions
โค๏ธ React with โค๏ธ for more SQL interview challenges!
You have 2 minutes to solve this SQL query.
Find the employees who joined in the last 30 days.
Assume the table structure:
employees(employee_id, employee_name, department, joining_date)
๐ ๐ฒ: Challenge accepted! ๐ช
SELECT
employee_id,
employee_name,
department,
joining_date
FROM employees
WHERE joining_date >= CURRENT_DATE - INTERVAL '30 days';
๐ก Explanation:
This query filters employees whose joining date falls within the last 30 days.
โข CURRENT_DATE returns today's date.
โข INTERVAL '30 days' subtracts 30 days from the current date.
โข The WHERE clause returns employees who joined on or after that date.
This question tests your understanding of:
โ Date Functions
โ Date Arithmetic
โ Filtering Records with Dates
๐ฏ Expected Output Example
Employee Department Joining Date
John IT 2026-06-10
Sarah HR 2026-06-22
๐ Database-Specific Alternatives
MySQL
SELECT *
FROM employees
WHERE joining_date >= CURDATE() - INTERVAL 30 DAY;
SQL Server
SELECT *
FROM employees
WHERE joining_date >= DATEADD(DAY, -30, GETDATE());
Oracle
SELECT *
FROM employees
WHERE joining_date >= SYSDATE - 30;
๐ Tip for SQL Job Seekers:
Date-related SQL questions are very common. Make sure you're comfortable with:
โข Finding records from the last N days
โข Current month/year filters
โข Date differences
โข Date formatting
โข Database-specific date functions
โค๏ธ React with โค๏ธ for more SQL interview challenges!
โค19
๐๐ป๐๐ฒ๐ฟ๐๐ถ๐ฒ๐๐ฒ๐ฟ:
You have 2 minutes to solve this SQL query.
Find the customer(s) who placed the highest number of orders.
Tables:
customers(customer_id, customer_name)
orders(order_id, customer_id, order_date)
๐ ๐ฒ: Challenge accepted! ๐ช
๐ก Explanation:
The query first counts the total number of orders placed by each customer and then ranks them based on the order count.
โ
โ
โ
โ The outer query returns all customers with
This question tests your understanding of:
โ JOIN
โ GROUP BY
โ Aggregate Functions COUNT
โ Window Functions DENSE_RANK
๐ฏ Expected Output Example
Both customers are returned because they are tied for the highest number of orders.
๐ Tip for SQL Job Seekers:
Whenever an interview asks for the highest, lowest, most, or least, think about whether multiple records could tie for first place. Using
โค๏ธ React with โค๏ธ for more SQL interview challenges!
You have 2 minutes to solve this SQL query.
Find the customer(s) who placed the highest number of orders.
Tables:
customers(customer_id, customer_name)
orders(order_id, customer_id, order_date)
๐ ๐ฒ: Challenge accepted! ๐ช
SELECT
customer_id,
customer_name,
total_orders
FROM (
SELECT
c.customer_id,
c.customer_name,
COUNT(o.order_id) AS total_orders,
DENSE_RANK() OVER (
ORDER BY COUNT(o.order_id) DESC
) AS rnk
FROM customers c
JOIN orders o
ON c.customer_id = o.customer_id
GROUP BY
c.customer_id,
c.customer_name
) ranked
WHERE rnk = 1;
๐ก Explanation:
The query first counts the total number of orders placed by each customer and then ranks them based on the order count.
โ
COUNT(o.order_id) calculates the number of orders per customer.โ
GROUP BY ensures one row per customer.โ
DENSE_RANK() ranks customers from highest to lowest order count.โ The outer query returns all customers with
rnk = 1, including ties.This question tests your understanding of:
โ JOIN
โ GROUP BY
โ Aggregate Functions COUNT
โ Window Functions DENSE_RANK
๐ฏ Expected Output Example
+----------+--------------+
| Customer | Total Orders |
+----------+--------------+
| John | 25 |
| Sarah | 25 |
+----------+--------------+
Both customers are returned because they are tied for the highest number of orders.
๐ Tip for SQL Job Seekers:
Whenever an interview asks for the highest, lowest, most, or least, think about whether multiple records could tie for first place. Using
DENSE_RANK() instead of LIMIT 1 makes your solution more robust and interview-ready.โค๏ธ React with โค๏ธ for more SQL interview challenges!
โค18
๐๐ป๐๐ฒ๐ฟ๐๐ถ๐ฒ๐๐ฒ๐ฟ:
You have 2 minutes to solve this SQL query.
Find all employees who have the same manager.
Assume the table structure:
employees(employee_id, employee_name, manager_id)
๐ ๐ฒ: Challenge accepted! ๐ช
SELECT
e.employee_id,
e.employee_name,
e.manager_id,
m.employee_name AS manager_name
FROM employees e
JOIN employees m
ON e.manager_id = m.employee_id
WHERE e.manager_id IN (
SELECT manager_id
FROM employees
WHERE manager_id IS NOT NULL
GROUP BY manager_id
HAVING COUNT(*) > 1
)
ORDER BY e.manager_id, e.employee_name;
๐ก Explanation:
This query identifies managers who supervise more than one employee and returns all employees reporting to those managers.
โ The subquery groups records by manager_id.
โ HAVING COUNT(*) > 1 finds managers with multiple direct reports.
โ A self join retrieves the manager's name.
โ The outer query returns every employee reporting to those managers.
This question tests your understanding of:
โ Self Joins
โ GROUP BY and HAVING
โ Subqueries
โ Organizational Hierarchies
๐ฏ Expected Output Example
Employee Manager
John David
Alice David
Sarah Michael
Bob Michael
๐ Alternative Using Window Functions
SELECT
employee_id,
employee_name,
manager_id
FROM (
SELECT
*,
COUNT(*) OVER (
PARTITION BY manager_id
) AS team_size
FROM employees
WHERE manager_id IS NOT NULL
) t
WHERE team_size > 1;
This approach uses a window function to count the number of employees under each manager without using GROUP BY.
๐ Tip for SQL Job Seekers:
Hierarchy-based questions are very common in interviews. Practice problems involving:
Employees and managers
Parent-child relationships
Organizational charts
Category trees
Recursive queries WITH RECURSIVE or recursive CTEs
โค๏ธ React with โค๏ธ for more SQL interview challenges!
You have 2 minutes to solve this SQL query.
Find all employees who have the same manager.
Assume the table structure:
employees(employee_id, employee_name, manager_id)
๐ ๐ฒ: Challenge accepted! ๐ช
SELECT
e.employee_id,
e.employee_name,
e.manager_id,
m.employee_name AS manager_name
FROM employees e
JOIN employees m
ON e.manager_id = m.employee_id
WHERE e.manager_id IN (
SELECT manager_id
FROM employees
WHERE manager_id IS NOT NULL
GROUP BY manager_id
HAVING COUNT(*) > 1
)
ORDER BY e.manager_id, e.employee_name;
๐ก Explanation:
This query identifies managers who supervise more than one employee and returns all employees reporting to those managers.
โ The subquery groups records by manager_id.
โ HAVING COUNT(*) > 1 finds managers with multiple direct reports.
โ A self join retrieves the manager's name.
โ The outer query returns every employee reporting to those managers.
This question tests your understanding of:
โ Self Joins
โ GROUP BY and HAVING
โ Subqueries
โ Organizational Hierarchies
๐ฏ Expected Output Example
Employee Manager
John David
Alice David
Sarah Michael
Bob Michael
๐ Alternative Using Window Functions
SELECT
employee_id,
employee_name,
manager_id
FROM (
SELECT
*,
COUNT(*) OVER (
PARTITION BY manager_id
) AS team_size
FROM employees
WHERE manager_id IS NOT NULL
) t
WHERE team_size > 1;
This approach uses a window function to count the number of employees under each manager without using GROUP BY.
๐ Tip for SQL Job Seekers:
Hierarchy-based questions are very common in interviews. Practice problems involving:
Employees and managers
Parent-child relationships
Organizational charts
Category trees
Recursive queries WITH RECURSIVE or recursive CTEs
โค๏ธ React with โค๏ธ for more SQL interview challenges!
โค15
๐ถ ASO Corgi โ platform for the App Store developers.
Find the keywords your apps and competitors rank for, and track positions across every country in one place.
๐ Keyword research: by topic, by your app's languages, from App Store suggestions, by competitors, and with AI analysis.
โข Rankings by country โ history, charts, demand score (0โ100)
โข Global search across any App Store storefront
โข ASO assistant builds your listing for each locale
โข App Store top charts for any country
๐ 14 days of Pro, free ๐ (no card required)
https://asocorgi.com/?promo=promo14&utm_source=sqlspecialist&utm_medium=telegram&utm_campaign=launch
Find the keywords your apps and competitors rank for, and track positions across every country in one place.
๐ Keyword research: by topic, by your app's languages, from App Store suggestions, by competitors, and with AI analysis.
โข Rankings by country โ history, charts, demand score (0โ100)
โข Global search across any App Store storefront
โข ASO assistant builds your listing for each locale
โข App Store top charts for any country
๐ 14 days of Pro, free ๐ (no card required)
https://asocorgi.com/?promo=promo14&utm_source=sqlspecialist&utm_medium=telegram&utm_campaign=launch
โค5
๐๐ผ๐ผ๐๐ ๐ฌ๐ผ๐๐ฟ ๐๐ฎ๐ฟ๐ฒ๐ฒ๐ฟ ๐๐ข๐ญ๐ก ๐๐ฅ๐๐ ๐๐ถ๐๐ฐ๐ผ ๐๐ผ๐๐ฟ๐๐ฒ๐ + ๐ฆ๐ต๐ผ๐๐ฐ๐ฎ๐๐ฒ ๐๐ถ๐ด๐ถ๐๐ฎ๐น ๐๐ฎ๐ฑ๐ด๐ฒ๐
๐ซStand out in the job market with globally recognized tech skills
โ 100% FREE Learning
โ Official Cisco Digital Badges
โ Self-Paced Online Courses
โ Beginner-Friendly Content
โ Hands-on Labs (Selected Courses)
โ Globally Recognized Skills
๐ ๐๐ป๐ฟ๐ผ๐น๐น ๐๐ผ๐ฟ ๐๐ฅ๐๐๐:
https://pdlink.in/4y0ACOI
๐ Start Learning Today. Earn Official Cisco Badges. Get Career Ready!
๐ซStand out in the job market with globally recognized tech skills
โ 100% FREE Learning
โ Official Cisco Digital Badges
โ Self-Paced Online Courses
โ Beginner-Friendly Content
โ Hands-on Labs (Selected Courses)
โ Globally Recognized Skills
๐ ๐๐ป๐ฟ๐ผ๐น๐น ๐๐ผ๐ฟ ๐๐ฅ๐๐๐:
https://pdlink.in/4y0ACOI
๐ Start Learning Today. Earn Official Cisco Badges. Get Career Ready!
โค4
๐๐ป๐๐ฒ๐ฟ๐๐ถ๐ฒ๐๐ฒ๐ฟ:
You have 2 minutes to solve this SQL query.
Find the departments where the average salary is greater than the company's overall average salary.
๐ ๐ฒ: Challenge accepted! ๐ช
SELECT
department,
AVG(salary) AS average_salary
FROM employees
GROUP BY department
HAVING AVG(salary) > (
SELECT AVG(salary)
FROM employees
);
๐ก Explanation:
The query compares each department's average salary with the company's overall average salary.
โข GROUP BY department calculates the average salary for each department.
โข The subquery computes the overall average salary across all employees.
โข HAVING filters only those departments whose average salary exceeds the company average.
This question tests your understanding of:
โ GROUP BY
โ HAVING
โ Aggregate Functions AVG
โ Subqueries
๐ฏ Expected Output Example
Department: Average Salary
IT: 88,500
Finance: 84,000
HR is excluded because its average salary is below the company average.
๐ Alternative Using a Common Table Expression CTE
WITH company_avg AS (
SELECT AVG(salary) AS avg_salary
FROM employees
)
SELECT
department,
AVG(salary) AS average_salary
FROM employees, company_avg
GROUP BY department, company_avg.avg_salary
HAVING AVG(salary) > company_avg.avg_salary;
Using a CTE can improve readability, especially when the same calculated value is reused in larger queries.
๐ Tip for SQL Job Seekers:
Interviewers often ask questions that compare group-level aggregates with overall aggregates. Master the use of HAVING with subqueriesโitโs a key SQL pattern.
โค๏ธ React with โค๏ธ for more SQL interview challenges!
You have 2 minutes to solve this SQL query.
Find the departments where the average salary is greater than the company's overall average salary.
๐ ๐ฒ: Challenge accepted! ๐ช
SELECT
department,
AVG(salary) AS average_salary
FROM employees
GROUP BY department
HAVING AVG(salary) > (
SELECT AVG(salary)
FROM employees
);
๐ก Explanation:
The query compares each department's average salary with the company's overall average salary.
โข GROUP BY department calculates the average salary for each department.
โข The subquery computes the overall average salary across all employees.
โข HAVING filters only those departments whose average salary exceeds the company average.
This question tests your understanding of:
โ GROUP BY
โ HAVING
โ Aggregate Functions AVG
โ Subqueries
๐ฏ Expected Output Example
Department: Average Salary
IT: 88,500
Finance: 84,000
HR is excluded because its average salary is below the company average.
๐ Alternative Using a Common Table Expression CTE
WITH company_avg AS (
SELECT AVG(salary) AS avg_salary
FROM employees
)
SELECT
department,
AVG(salary) AS average_salary
FROM employees, company_avg
GROUP BY department, company_avg.avg_salary
HAVING AVG(salary) > company_avg.avg_salary;
Using a CTE can improve readability, especially when the same calculated value is reused in larger queries.
๐ Tip for SQL Job Seekers:
Interviewers often ask questions that compare group-level aggregates with overall aggregates. Master the use of HAVING with subqueriesโitโs a key SQL pattern.
โค๏ธ React with โค๏ธ for more SQL interview challenges!
โค12
๐ ๐๐ผ๐ผ๐ด๐น๐ฒ ๐๐ฅ๐๐ ๐๐ ๐๐ผ๐๐ฟ๐๐ฒ๐ ๐ช๐ถ๐๐ต ๐๐ผ๐บ๐ฝ๐น๐ฒ๐๐ถ๐ผ๐ป ๐๐ฎ๐ฑ๐ด๐ฒ๐ ๐ฅ
Google is offering free AI courses with completion badges to help students & professionals build in-demand AI skills ๐
โจ Learn from Google Experts
โจ Earn Google Completion Badges
โจ Boost Your Resume & LinkedIn Profile
โจ Build In-Demand AI Skills for 2026
๐ ๐๐ป๐ฟ๐ผ๐น๐น ๐๐ผ๐ฟ ๐๐ฅ๐๐๐:
https://pdlink.in/49lCYxa
๐ฅ Start your AI journey today and future-proof your career with Google AI learning programs.
Google is offering free AI courses with completion badges to help students & professionals build in-demand AI skills ๐
โจ Learn from Google Experts
โจ Earn Google Completion Badges
โจ Boost Your Resume & LinkedIn Profile
โจ Build In-Demand AI Skills for 2026
๐ ๐๐ป๐ฟ๐ผ๐น๐น ๐๐ผ๐ฟ ๐๐ฅ๐๐๐:
https://pdlink.in/49lCYxa
๐ฅ Start your AI journey today and future-proof your career with Google AI learning programs.
โค3
Want to become a pro in Data Analytics and crack interviews?
Focus on these key topics: ๐
1) Understand Data Analytics basics & tools
2) Learn Excel for data cleaning & analysis
3) Master SQL for data querying
4) Study data visualization principles
5) Get hands-on with Power BI/Tableau dashboards
6) Explore statistics & probability fundamentals
7) Learn data wrangling and preprocessing
8) Understand data storytelling and report writing
9) Practice hypothesis testing & A/B testing
10) Get familiar with Python/R for analytics (optional but helpful)
11) Work on real datasets and case studies (Kaggle is great)
12) Build end-to-end projects from data collection to visualization
13) Learn how to communicate insights effectively
14) Practice problem-solving with datasets regularly
15) Optimize your resume with analytics keywords
16) Follow analytics experts and tutorials on YouTube/LinkedIn
Pro tip: Search each topic on YouTube and watch short 10-15 min videos. Practice alongside to build strong fundamentals.
17) Finally, watch full data analytics project walkthroughs and try them yourself.
18) Learn integration of SQL and Power BI/Tableau for advanced reporting.
Credits: https://t.me/sqlspecialist
React โค๏ธ for more
Focus on these key topics: ๐
1) Understand Data Analytics basics & tools
2) Learn Excel for data cleaning & analysis
3) Master SQL for data querying
4) Study data visualization principles
5) Get hands-on with Power BI/Tableau dashboards
6) Explore statistics & probability fundamentals
7) Learn data wrangling and preprocessing
8) Understand data storytelling and report writing
9) Practice hypothesis testing & A/B testing
10) Get familiar with Python/R for analytics (optional but helpful)
11) Work on real datasets and case studies (Kaggle is great)
12) Build end-to-end projects from data collection to visualization
13) Learn how to communicate insights effectively
14) Practice problem-solving with datasets regularly
15) Optimize your resume with analytics keywords
16) Follow analytics experts and tutorials on YouTube/LinkedIn
Pro tip: Search each topic on YouTube and watch short 10-15 min videos. Practice alongside to build strong fundamentals.
17) Finally, watch full data analytics project walkthroughs and try them yourself.
18) Learn integration of SQL and Power BI/Tableau for advanced reporting.
Credits: https://t.me/sqlspecialist
React โค๏ธ for more
โค17
โ๏ธ ๐๐ถ๐ฐ๐ธ๐๐๐ฎ๐ฟ๐ ๐ฌ๐ผ๐๐ฟ ๐๐ช๐ฆ ๐๐ผ๐๐ฟ๐ป๐ฒ๐ | ๐๐ฅ๐๐ ๐๐ช๐ฆ ๐๐ฒ๐ฟ๐๐ถ๐ณ๐ถ๐ฐ๐ฎ๐๐ถ๐ผ๐ป ๐๐ผ๐๐ฟ๐๐ฒ๐๐
โ๏ธ High-Demand Cloud Skills
โ๏ธ Prepare for AWS Certifications
โ๏ธ Strengthen Your Resume & LinkedIn
โ๏ธ Unlock Opportunities in Cloud, AI & DevOps
๐ ๐๐ป๐ฟ๐ผ๐น๐น ๐๐ผ๐ฟ ๐๐ฅ๐๐๐:
https://pdlinks.in/ed7
๐ Start Learning Today. Build Cloud Skills. Accelerate Your Tech Career!
โ๏ธ High-Demand Cloud Skills
โ๏ธ Prepare for AWS Certifications
โ๏ธ Strengthen Your Resume & LinkedIn
โ๏ธ Unlock Opportunities in Cloud, AI & DevOps
๐ ๐๐ป๐ฟ๐ผ๐น๐น ๐๐ผ๐ฟ ๐๐ฅ๐๐๐:
https://pdlinks.in/ed7
๐ Start Learning Today. Build Cloud Skills. Accelerate Your Tech Career!
โค2
I see so many people jump into data analytics, excited by its popularity, only to feel lost or uninterested soon after. I get it, data isnโt for everyone, and thatโs okay.
Data analytics requires a certain spark or say curiosity. You need that drive to dig deeper, to understand why things happen, to explore how data pieces connect to reveal a bigger picture. Without that spark, itโs easy to feel overwhelmed or even bored.
Before diving in, ask yourself, Do I really enjoy solving puzzles? Am I genuinely excited about numbers, patterns, and insights? If youโre curious and love learning, data can be incredibly rewarding. But if itโs just about following a trend, it might not be a fulfilling path for you.
Be honest with yourself. Find your passion, whether itโs in data or somewhere else and invest in something that truly excites you.
Hope this helps you ๐
Data analytics requires a certain spark or say curiosity. You need that drive to dig deeper, to understand why things happen, to explore how data pieces connect to reveal a bigger picture. Without that spark, itโs easy to feel overwhelmed or even bored.
Before diving in, ask yourself, Do I really enjoy solving puzzles? Am I genuinely excited about numbers, patterns, and insights? If youโre curious and love learning, data can be incredibly rewarding. But if itโs just about following a trend, it might not be a fulfilling path for you.
Be honest with yourself. Find your passion, whether itโs in data or somewhere else and invest in something that truly excites you.
Hope this helps you ๐
โค25