SQL Learning Repository

A structured collection of SQL exercises using PostgreSQL databases for film rental and flight booking scenarios.

Project Structure

sql-learning/
├── sql-exercises/     # All SQL practice files (89 files)
├── databases/         # Database schemas and setup
├── docs/             # Documentation and reference
└── README.md         # This file

Prerequisites

• PostgreSQL 13 or higher
• pgAdmin or similar database client

Setup

1. Install PostgreSQL
2. Create databases:

   CREATE DATABASE greencycle_rental;
   CREATE DATABASE flights_booking;

3. Download databases from Kaggle

Usage

SQL exercises are organized by difficulty level and topic in the sql-exercises/ directory:

• L1_ - Level 1 Fundamentals (SELECT, WHERE, basic functions)
• L2_ - Level 2 Intermediate (JOINs, GROUP BY, subqueries)
• L3_ - Level 3 Advanced (Window functions, complex analytics)
• L4_ - Level 4 Administration (DDL, views, procedures, security)
• P1-P3_ - Business Projects (GreenCycle, Employee, Advanced analysis)
• PRACTICE_ - Challenge exercises

Database Information

• GreenCycle Database: Film rental business with customers, films, and rental transactions
• Flights Database: Flight booking system with airports, flights, and passenger data

See databases/database-schemas/ for entity relationship diagrams.

Learning Path

1. Level 1 Fundamentals: Start with L1_SELECT-basics-customer-data.sql
2. Level 2 Intermediate: Progress to L2_JOIN-* and L2_GROUP-* files
3. Level 3 Advanced: Master L3_WINDOW-* and L3_SUBQUERY-* files
4. Level 4 Administration: Complete L4_DDL-* and L4_PROCEDURES-* files
5. Business Projects: Apply skills with P1_FILMS-*, P2_EMPLOYEES-* files
6. Practice Challenges: Test knowledge with PRACTICE_* files

Documentation

Additional reference materials are available in the docs/ directory.