HackerRank SQL Practice Repository 🎯

Welcome to the HackerRank-SQL repository! 🚀 This repo contains solutions to SQL problems from the HackerRank SQL Preparation Kit. Whether you're brushing up your SQL skills or starting fresh, this is the perfect place to practice and learn! 💻📚

Table of Contents

• Overview
• Problem List
• How to Contribute
• Getting Started
• License
• Acknowledgements

Overview

The HackerRank SQL Preparation Kit contains a set of problems that cover a wide range of SQL topics, including:

• Basic SELECT queries
• Aggregations
• Joins
• Subqueries
• Data manipulation
• And more...

By solving these problems, you will improve your understanding of SQL concepts and be well-prepared for SQL-based challenges in interviews and exams.

📋 Problem Table

Here is a list of all the problems from the HackerRank SQL Preparation Kit with links to each problem:

#	Problem Title	Link
1	Revising the Select Query I	Link
2	Revising the Select Query II	Link
3	Select All	Link
4	Select By ID	Link
5	Japanese Cities' Attributes	Link
6	Japanese Cities' Names	Link
7	Average Population	Link
8	Japan Population	Link
9	Revising Aggregations - The Count Function	Link
10	Revising Aggregations - The Sum Function	Link
11	Revising Aggregations - Averages	Link
12	Population Density Difference	Link
13	African Cities	Link
14	Asian Population	Link
15	Average Population of Each Continent	Link
16	Weather Observation Station 1	Link
17	Weather Observation Station 2	Link
18	Weather Observation Station 3	Link
19	Weather Observation Station 4	Link
20	Weather Observation Station 5	Link
21	Weather Observation Station 6	Link
22	Top Competitors	Link
23	Who's the Winner	Link
24	Contest Leaderboard	Link
25	Contest Leaderboard II	Link
26	Non-Divisible Numbers	Link
27	Reciprocal Relationship	Link
28	Duplicate Numbers	Link
29	Sorting Dates	Link
30	Counting Characters	Link
31	The "Run-Length" Problem	Link
32	Substring Matching	Link
33	Substring Matching II	Link
34	Kth Smallest Element	Link
35	Group By Problem	Link
36	Average Age	Link
37	Listing Friends	Link
38	Find the Highest Salaries	Link
39	Second Highest Salary	Link
40	Rank Employees	Link
41	Dense Rank	Link
42	Find the City with Most Population	Link
43	Find the Median Salary	Link
44	List of Countries	Link
45	The "First and Last" Problem	Link
46	The "Nth Greatest" Problem
47	Employee Salaries	Link
48	Top Earners	Link
49	Weather Observation Station 7	Link
50	Weather Observation Station 8	Link
51	Weather Observation Station 9	Link
52	Weather Observation Station 10	Link
53	Weather Observation Station 11	Link
54	Weather Observation Station 12	Link
55	Weather Observation Station 13	Link
56	Weather Observation Station 14	Link
57	Weather Observation Station 15	Link
58	Weather Observation Station 16	Link
59	Weather Observation Station 17	Link
60	Weather Observation Station 18	Link
61	Weather Observation Station 19	Link
62	Weather Observation Station 20	Link

🚀 How to Contribute

1. 🍴 Fork the repository.
2. 🖥️ Clone the repository to your local machine.
3. 🌱 Create a new branch for your changes.
4. 🛠️ Add your solutions or improve documentation.
5. 📤 Commit your changes and push them to your forked repository.
6. 🔁 Open a pull request to merge your changes.

🛠️ Getting Started

1. Visit the HackerRank SQL Preparation Kit.
2. Solve problems directly on HackerRank. 🧑‍💻
3. Save and organize your solutions in this repository. 🗂️

Acknowledgements

A big thank you to HackerRank for providing such a fantastic platform to practice and learn SQL. 🎉👏

Happy learning and coding! 🚀✨