Now, let’s move to the next topic of SQL Roadmap:

✅ HAVING Clause

🧠 1. What is HAVING?

HAVING is used to filter grouped data

👉 Think like this:
- WHERE → filters rows (before grouping)
- HAVING → filters groups (after grouping)

⚡ 2. WHERE vs HAVING

Works on
- WHERE: Rows
- HAVING: Groups

Used with
- WHERE: SELECT
- HAVING: GROUP BY

Can use aggregates?
- WHERE: ❌ No
- HAVING: ✅ Yes

💡 3. Basic Syntax

SELECT column, AGG_FUNCTION(column)
FROM table_name
GROUP BY column
HAVING condition;

🎯 4. Examples (Very Important)

👉 Example 1: Departments with more than 2 employees

SELECT department, COUNT() AS total_emp
FROM employees
GROUP BY department
HAVING COUNT() > 2;

👉 Example 2: Departments with average salary > 50k

SELECT department, AVG(salary) AS avg_salary
FROM employees
GROUP BY department
HAVING AVG(salary) > 50000;

⚡ 5. WHERE + HAVING Together

SELECT department, COUNT() AS total_emp
FROM employees
WHERE salary > 30000
GROUP BY department
HAVING COUNT() > 2;

👉 Step-by-step:
1. WHERE → filters employees with salary > 30k
2. GROUP BY → groups by department
3. HAVING → keeps only groups with > 2 employees

🎯 6. Practice Tasks
1. Find departments having more than 3 employees
2. Find departments with average salary > 60k
3. Count employees per department where salary > 40k
4. Show departments with total salary > 1,00,000
5. Find departments with minimum salary > 30k

⚡ Mini Challenge 🔥

👉 Find departments having more than 2 employees AND avg salary > 50k

Double Tap ❤️ For Practice Task Solution