Skip to content

Latest commit

 

History

History
44 lines (22 loc) · 3.67 KB

README.md

File metadata and controls

44 lines (22 loc) · 3.67 KB
Raw

LeetCode Solutions - SQL

This repository provides a carefully curated collection of SQL solutions for various LeetCode problems, organized around fundamental SQL concepts. It is designed to support anyone looking to strengthen their SQL skills through practical problem-solving. The repository covers a wide range of SQL topics, each demonstrated through real-world examples and optimized queries.

Repository Overview

The solutions included span from basic to advanced SQL topics, offering insights into each concept’s usage and optimization. Topics covered include:

  • Control Flow and Conditional Logic: Solutions that demonstrate the use of conditional statements like CASE and flow control to handle complex logic within queries. These examples showcase scenarios where data needs to be processed or transformed based on specific conditions.

  • Functions: Includes examples of both aggregate functions (such as SUM, COUNT, AVG) and scalar functions (like ROUND, ABS, LENGTH) that are often used to summarize or process data in useful ways.

  • Joins: Comprehensive solutions that illustrate various types of joins (e.g., INNER, LEFT, RIGHT, and FULL OUTER) to combine data across multiple tables. These examples are crucial for understanding relationships in relational databases and extracting meaningful insights from connected datasets.

  • Numerical and String Processing: Provides solutions involving numerical functions and string manipulations, such as calculations, string replacements, concatenations, and format adjustments. These skills are vital for data transformation and preparation tasks.

  • Data Selection and Ordering: A variety of examples that cover SELECT statements, filtering with WHERE, and sorting with ORDER BY. These basic yet powerful SQL operations form the foundation of any database query.

  • Unions and Set Operations: Solutions using UNION and UNION ALL to combine results from multiple queries, demonstrating how to handle large, diverse datasets and retrieve comprehensive results across tables.

Each solution is crafted to provide clear, optimal results while following best practices in SQL querying. The examples are also well-commented to explain the purpose and outcome of each line, making it easy for readers to understand both the syntax and the logic.

Purpose and Usage

This repository serves multiple purposes:

  1. Learning Resource: Whether you’re new to SQL or looking to solidify your skills, this repository provides structured guidance through practical examples. Each problem solution reinforces SQL syntax, key concepts, and query optimization techniques.

  2. Interview Preparation: SQL is commonly tested in technical interviews, and this repository offers a relevant and up-to-date resource to practice SQL questions found on LeetCode. By studying these solutions, users can prepare to tackle similar problems in interview scenarios.

  3. Quick Reference: With organized folders and categorized examples, this repository acts as a quick reference guide for specific SQL commands, functions, or query structures.

  4. Problem-Solving Practice: LeetCode SQL problems are often challenging, and working through them in this structured manner helps users develop a methodical approach to SQL problem-solving.

Contributions

Contributions to this repository are encouraged. Whether you want to add new solutions, improve existing ones, or provide alternative query strategies, your input is welcome. Contributions enhance the resource for the entire SQL learning community.

License

This project is licensed under the MIT License, making it accessible for personal and educational use.

Happy learning and querying!