📘 SQL GROUP BY & HAVING Tutorial

📘 SQL Tutorial: GROUP BY and HAVING with Examples (Bangla Style)

GROUP BY and HAVING clauses are very useful in SQL for grouping and filtering data based on aggregation. Below is a practical tutorial using Bangladeshi names.

📋 Sample employees Table:

employee_id	name	department_id	job_id	salary
201	Arif	10	HR	50000
202	Nasrin	20	ENG	60000
203	Faruk	10	HR	55000
204	Ritu	30	MKT	45000
205	Imran	20	ENG	62000

🔹 1. Count Employees per Department

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

Output:

department_id	employee_count
10	2
20	2
30	1

🔹 2. Departments with More Than 1 Employee

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

Output:

department_id	employee_count
10	2
20	2

🔹 3. Total Salary by Department

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

Output:

department_id	total_salary
10	105000
20	122000
30	45000

🔹 4. Departments Where Total Salary > 100000

SELECT department_id, SUM(salary) AS total_salary
FROM employees
GROUP BY department_id
HAVING SUM(salary) > 100000;

Output:

department_id	total_salary
10	105000
20	122000

🔹 5. Average Salary per Job Title

SELECT job_id, AVG(salary) AS avg_salary
FROM employees
GROUP BY job_id;

Output:

job_id	avg_salary
HR	52500
ENG	61000
MKT	45000

🔹 6. Job Titles with More Than 1 Employee

SELECT job_id, COUNT(*) AS emp_count
FROM employees
GROUP BY job_id
HAVING COUNT(*) > 1;

Output:

job_id	emp_count
HR	2
ENG	2

SQL GROUP BY, HAVING, Bangla SQL tutorial, SQL with Bangladeshi names, SQL GROUP BY explained, SQL blog, MySQL examples, Oracle GROUP BY HAVING, SQL beginner queries, GROUP BY Bangla style