SQL Programming Resources on Telegram: “✅ SQL Coding Interview Questions with Answers: P…”

✅ SQL Coding Interview Questions with Answers: Part 3 📊💻

1️⃣ Get Highest Salary Per Department
Table: Employees
Columns: id, name, dept, salary

SELECT dept, MAX(salary) AS highest_salary  
FROM Employees  
GROUP BY dept;

Use case: Department-wise pay analysis.

2️⃣ Find Employees Without Matching Department
Tables: Employees, Departments

SELECT e.*  
FROM Employees e  
LEFT JOIN Departments d  
ON e.dept_id = d.id  
WHERE d.id IS NULL;

Use case: Data quality checks after joins.

3️⃣ Delete Duplicate Records but Keep One
Table: Users
Column: email

DELETE FROM Users  
WHERE id NOT IN (  
  SELECT MIN(id)  
  FROM Users  
  GROUP BY email  
);

Use case: Cleanup before analytics.

4️⃣ Find Nth Highest Salary (Example: 3rd)
Table: Employees

SELECT salary  
FROM (  
  SELECT salary,  
         DENSE_RANK() OVER (ORDER BY salary DESC) AS rnk  
  FROM Employees  
) t  
WHERE rnk = 3;

Use case: Works even with duplicate salaries.

5️⃣ Swap Gender Values
Table: Employees
Column: gender (M, F)

UPDATE Employees  
SET gender =  
CASE  
  WHEN gender = 'M' THEN 'F'  
  WHEN gender = 'F' THEN 'M'  
END;

Use case: Data correction tasks.

6️⃣ Find Employees with Odd IDs
Table: Employees

SELECT *  
FROM Employees  
WHERE id % 2 = 1;

Use case: Common filter logic question.

7️⃣ Get Running Total of Salary
Table: Employees
Column: salary

SELECT id, salary,  
SUM(salary) OVER (ORDER BY id) AS running_total  
FROM Employees;

Use case: Used in financial and growth reports.

💬 Tap ❤️ for Part 4!