🧪 Practice SQL: Salary & Department Counts

🧪 SQL Practice: Salary Summaries & Department Counts

Try the following SQL queries using this sample employee data. Practice grouping by departments, counting employees, and calculating salary aggregates.

📋 Sample employees Table:

employee_id	name	department_id	salary
1	Arif	101	50000
2	Nasrin	101	52000
3	Rafi	102	47000
4	Ritu	103	60000
5	Faruk	101	51000

📝 Practice Queries:

1️⃣ Total Salary Paid Per Department

Goal: Find the total salary for each department.

SELECT department_id, SUM(salary) AS total_salary
FROM employees
GROUP BY department_id;

Expected Output:

department_id	total_salary
101	153000
102	47000
103	60000

2️⃣ Employee Count Per Department

Goal: Count the number of employees in each department.

SELECT department_id, COUNT(*) AS employee_count
FROM employees
GROUP BY department_id;

Expected Output:

department_id	employee_count
101	3
102	1
103	1

3️⃣ Average Salary of Departments with More Than 1 Employee

Goal: Show average salary for departments with more than 1 employee.

SELECT department_id, AVG(salary) AS avg_salary
FROM employees
GROUP BY department_id
HAVING COUNT(*) > 1;

Expected Output:

department_id	avg_salary
101	51000

📌 Tips:

• Use SUM(), AVG(), COUNT() for aggregation.
• GROUP BY groups rows by column.
• HAVING filters grouped results (like WHERE, but after grouping).

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