#SQL
This repository is a collection of SQL notes, queries, and practice problems designed to help you learn and revise SQL effectively. Whether you're a beginner or preparing for interviews, this repo covers essential SQL concepts with examples and hands-on exercises.
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📒 Topic-wise Notes
Covers core SQL topics such as:- DDL (CREATE, ALTER, DROP)
- DML (INSERT, UPDATE, DELETE)
- SELECT Queries
- WHERE, GROUP BY, HAVING, ORDER BY
- JOINS (INNER, LEFT, RIGHT, FULL)
- Subqueries & Nested Queries
- Constraints (Primary Key, Foreign Key, NOT NULL, UNIQUE)
- Views & Indexes
- Transactions and ACID properties
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🧠 Practice Queries
- Simple to advanced level queries
- Real-world scenarios
- Query optimization examples
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🧪 Sample Database Schemas
- Ready-to-use schemas for testing queries
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🧾 Interview Questions
- Common SQL interview questions with answers
- Query-based coding challenges
- ✅ Compatible with MySQL, PostgreSQL, and SQLite
- 📂 SQL files organized by topic for easy access
- Students preparing for placement & interviews
- Beginners starting with SQL
- Developers revising SQL concepts
- Anyone exploring relational databases