Comprehensive SQL Learning Path

A structured guide to mastering SQL from basics to advanced concepts.

Quick Start Guide

Prerequisites

• Basic understanding of databases
• Access to a SQL database (MySQL, PostgreSQL, SQL Server, etc.)
• Text editor or IDE (VS Code recommended)

Installation Requirements

1. Database Server (choose one):

   • MySQL: Download
   • PostgreSQL: Download
   • SQL Server Express: Download

2. Database GUI Tool (optional):

   • MySQL Workbench
   • pgAdmin
   • Azure Data Studio
   • DBeaver

Repository Structure

SQL/
├── 00_Learning_Roadmap.md           # Overall learning guide
├── 01_Fundamentals/                 # SQL basics
│   ├── 01_Database_Basics.md       # Database concepts
│   ├── 02_SQL_Commands.md          # Basic SQL commands
│   └── 03_Basic_Queries.md         # Simple queries
│
├── 02_Data_Manipulation/           # Working with data
│   ├── 01_Data_Types_and_Operators.md
│   ├── 02_Functions_and_Procedures.md
│   └── 03_Advanced_Operations.md
│
├── 03_Joins_and_Relationships/     # Table relationships
│   ├── 01_Join_Types.md           # Different types of JOINs
│   ├── 02_Subqueries.md           # Nested queries
│   └── 03_Advanced_Relationships.md
│
├── 04_Advanced_Concepts/          # Advanced topics
│   ├── 01_Query_Optimization.md
│   ├── 02_Window_Functions.md
│   ├── 03_Views_and_Procedures.md
│   ├── 04_Database_Administration.md
│   └── 05_Advanced_SQL_Functions.md
│
└── 05_Practice_Problems/          # Practice exercises
    ├── leetcode.md
    ├── 01_LeetCode_HackerRank_Solutions.md
    ├── 02_Real_World_Case_Studies.md
    ├── 03_Advanced_LeetCode_Solutions.md
    ├── 04_Interview_Style_Problems.md
    ├── 05_Problem_Patterns_and_Optimization.md
    └── 06_Performance_Monitoring.md

How to Use This Repository

1. Start with the 01_Fundamentals section
2. Complete each section sequentially
3. Practice with examples in each module
4. Solve problems in 06_Practice_Problems
5. Test your knowledge with interview questions

Learning Path

Level 1: Basics (2-3 weeks)

1. SQL fundamentals
2. Basic queries
3. CRUD operations

Level 2: Data Manipulation (2-3 weeks)

1. Functions and operators
2. Stored procedures
3. Transactions

Level 3: Relationships (3-4 weeks)

1. JOIN operations
2. Subqueries
3. Database design

Level 4: Advanced Topics (4-6 weeks)

1. Window functions
2. Query optimization
3. Performance tuning

Level 5: Professional Skills (4-6 weeks)

1. Real-world problems
2. Best practices
3. Interview preparation

Best Practices

1. Query Writing

• Use appropriate indentation
• Write clear, readable queries
• Comment complex logic
• Consider performance impact

2. Database Design

• Follow normalization rules
• Use appropriate data types
• Implement proper constraints
• Design efficient indexes

3. Performance

• Write optimized queries
• Use appropriate indexes
• Monitor query performance
• Regular maintenance

Interview Preparation

Key Topics

1. Query optimization
2. Database design
3. Indexing strategies
4. Performance tuning
5. Common problems and solutions

Practice Areas

1. LeetCode SQL Problems - 88+ problems with solutions (Easy/Medium/Hard)
2. Real-world scenarios
3. Performance optimization
4. System design questions

🎯 LeetCode SQL Problems Collection

This repository includes a comprehensive collection of 88+ LeetCode SQL problems with detailed solutions:

Problem Categories:

• Easy Problems: 50+ problems covering basic SQL concepts
• Medium Problems: 25+ problems with intermediate complexity
• Hard Problems: 13+ advanced problems for expert-level practice

What's Included:

• ✅ Complete SQL solutions for each problem
• ✅ Direct links to LeetCode problem descriptions
• ✅ Organized by difficulty level
• ✅ Covers all major SQL concepts: JOINs, subqueries, window functions, aggregations, and more

📁 Location: 05_Practice_Problems/leetcode.md

Additional Resources

Online Practice

• LeetCode: https://leetcode.com/
• HackerRank: https://www.hackerrank.com/
• SQL Zoo: https://sqlzoo.net/

Cheat Sheet

• SQL:cheatsheet
• regex:regex

Happy Learning! 🚀