SQL Employees Analysis

MySQL project with two parts: queries on the employees database and designing a small database

Part 1. Queries on the employees database

• Average salary by year and by department
• Departments with more than 15,000 current employees
• Top 10 employees with the biggest difference from their department's average salary
• Second manager of each department

Part 2. Database design

• Created a course management database with three tables (students, teachers, courses) linked by foreign keys
• Created and found duplicate rows

Techniques used

JOINs, GROUP BY / HAVING, CTEs, window functions (ROW_NUMBER), CREATE TABLE with primary and foreign keys, transactions