SQL Basics & Data Filtering

📋 Base Database Structure

1. The SELECT Statement

💼 Business Scenario:Corporate operations team needs to view all rows and baseline metrics across regional branches.

SELECT employee_id, employee_name, department, salary 
FROM employees;

2. The DISTINCT Clause

💼 Business Scenario:HR needs a unique audit list of active organizational departments without duplicated data.

SELECT DISTINCT department 
FROM employees;

3. The WHERE Clause

💼 Business Scenario:Engineering leadership requests compensation reports restricted exclusively to the 'Tech' department.

SELECT employee_name, salary 
FROM employees 
WHERE department = 'Tech';

4. The ORDER BY Clause

💼 Business Scenario:Executive board wants employee roster organized from highest salary package descending to lowest.

SELECT employee_name, salary 
FROM employees 
ORDER BY salary DESC;

5. The LIMIT / TOP Clause

💼 Business Scenario:Internal review lists require extracting simply the absolute top single earner in the table.

SELECT employee_name, salary 
FROM employees 
ORDER BY salary DESC 
LIMIT 1;

6. The IN Operator

💼 Business Scenario:Regional heads filter employees operating specifically from core hubs in 'Noida' or 'Mumbai'.

SELECT employee_name, city 
FROM employees 
WHERE city IN ('Noida', 'Mumbai');

7. The BETWEEN Operator

💼 Business Scenario:HR audits staff earning standard middle-tier packages between ₹60,000 and ₹85,000 inclusive.

SELECT employee_name, salary 
FROM employees 
WHERE salary BETWEEN 60000 AND 85000;

8. The LIKE Operator

💼 Business Scenario:Marketing search indexes need to pull rows where the employee name matches patterns starting with letter 'A'.

SELECT employee_name, department 
FROM employees 
WHERE employee_name LIKE 'A%';