SQL Programming Resources on Telegram: “✅ SQL Coding Questions with Answers: Part-1 📊💻…”

✅ SQL Coding Questions with Answers: Part-1 📊💻

1️⃣ Get the Second Highest Salary
Table: Employees
| id | name | salary |
|----|---------|--------|
| 1 | Alice | 5000 |
| 2 | Bob | 7000 |
| 3 | Charlie | 7000 |
| 4 | David | 6000 |

Query:

SELECT MAX(salary) AS Second_Highest
FROM Employees
WHERE salary < (
  SELECT MAX(salary) FROM Employees
);

This returns the highest salary less than the maximum—i.e., the second highest.

2️⃣ Count Employees Per Department
Table: Employees
| id | name | dept |
|----|--------|--------|
| 1 | Alice | HR |
| 2 | Bob | IT |
| 3 | Clara | IT |
| 4 | Dan | Sales |

Query:

SELECT dept, COUNT(*) AS total_employees  
FROM Employees  
GROUP BY dept;

This groups employees by department and counts how many are in each.

3️⃣ Find Duplicate Emails
Table: Users
| id | email |
|----|------------------|
| 1 | a@gmail.com |
| 2 | b@gmail.com |
| 3 | a@gmail.com |

Query:

SELECT email, COUNT(*) AS count  
FROM Users  
GROUP BY email  
HAVING COUNT(*) > 1;

Returns all emails that appear more than once.

4️⃣ Get Top 2 Salaries Per Department
Table: Employees
| id | name | dept | salary |
|----|--------|-------|--------|
| 1 | Alice | IT | 7000 |
| 2 | Bob | IT | 6500 |
| 3 | Clara | HR | 6000 |
| 4 | Dan | HR | 5900 |

Query:

SELECT * FROM (
  SELECT *, RANK() OVER (PARTITION BY dept ORDER BY salary DESC) AS rnk  
  FROM Employees  
) AS ranked  
WHERE rnk <= 2;

Ranks salaries within each department and returns top 2 per group.

5️⃣ Employees With No Manager Assigned
Table: Employees
| id | name | manager_id |
|----|-------|------------|
| 1 | John | NULL |
| 2 | Sarah | 1 |
| 3 | Alex | 2 |

Query:

SELECT * FROM Employees  
WHERE manager_id IS NULL;

Returns employees without any assigned manager.

💬 Double Tap ❤️ for Part-2!