🚀 Using HAVING Clause in Oracle SQL (Filtering Grouped Data)

As part of my ongoing learning with Oracle Autonomous Database, I explored the HAVING clause in SQL, which is used to filter grouped data. This is especially useful when working with aggregate functions.

🎯 Objective

The goal of this activity was to:

Understand how to filter grouped results Use HAVING with aggregate functions Perform advanced SQL queries

💻 Step 1: Creating the Table

CREATE TABLE employees (

emp_id NUMBER,

emp_name VARCHAR2(50),

department VARCHAR2(50),

salary NUMBER );

🧪 Step 2: Inserting Data

INSERT INTO employees VALUES (1, 'Ali', 'IT', 50000);

INSERT INTO employees VALUES (2, 'Ahmed', 'HR', 70000);

INSERT INTO employees VALUES (3, 'Sara', 'IT', 60000);

INSERT INTO employees VALUES (4, 'Zara', 'HR', 65000);

INSERT INTO employees VALUES (5, 'Usman', 'IT', 55000);

📊 Step 3: Grouping Data

SELECT department, COUNT( ) AS total_employees

FROM employees GROUP BY department;

🔍 Step 4: Filtering Groups using HAVING

SELECT department, COUNT() AS total_employees

FROM employees GROUP BY department HAVING COUNT(*) > 2;

This query filters only those departments that have more than 2 employees.

💡 What I Learned Difference between WHERE and HAVING

Filtering grouped data using HAVING Writing more advanced SQL queries

🚀 Conclusion

This activity helped me understand how to filter grouped data effectively using the HAVING clause. It is a powerful feature when working with aggregated results in Oracle SQL.