🧩 LeetCode SQL 50 – My SQL Solutions

This repository contains my solutions to the LeetCode SQL 50 study plan.
Each problem has its own folder containing:

• solution.sql — SQL query

• README.md — problem description, examples, and explanation

• runtime.png — screenshot of my submission runtime on LeetCode

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📂 Repository Structure

LeetCode-SQL-50/
│
├── 01-Recyclable-and-Low-Fat-Products/
│   ├── solution.sql
│   ├── runtime.png
│   └── README.md
│
├── 02-Find-Customer-Referee/
│   ├── solution.sql
│   ├── runtime.png
│   └── README.md
│
├── 03-Big-Countries/
│   ├── solution.sql
│   ├── runtime.png
│   └── README.md
│
│   ... (continues for all 50 problems)
│
└── README.md

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🧠 Topics Covered

• Basic SQL
• SELECT, WHERE
• ORDER BY, DISTINCT
• Aggregate Functions (COUNT, SUM, AVG)
• GROUP BY & HAVING
• JOIN (INNER, LEFT, RIGHT)
• UNION & Subqueries
• Window Functions
• Ranking Functions (RANK, DENSE_RANK, ROW_NUMBER)
• Advanced SQL Pattern

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🎯 Goal

To strengthen SQL query writing, database problem-solving skills, and improve preparation for data-related roles by solving all 50 problems from the LeetCode SQL Study Plan.

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🔗 Reference

📘 LeetCode Study Plan: Top SQL 50 (https://leetcode.com/studyplan/top-sql-50/)