https://github.com/iankitnegi/hackerranksqlvault
A repository of SQL solutions to HackerRank challenges, featuring well-documented queries and insights to enhance SQL skills. Perfect for learning and practice!
https://github.com/iankitnegi/hackerranksqlvault
mysql sql
Last synced: about 1 year ago
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A repository of SQL solutions to HackerRank challenges, featuring well-documented queries and insights to enhance SQL skills. Perfect for learning and practice!
- Host: GitHub
- URL: https://github.com/iankitnegi/hackerranksqlvault
- Owner: iankitnegi
- Created: 2024-12-08T14:19:19.000Z (over 1 year ago)
- Default Branch: main
- Last Pushed: 2024-12-09T13:24:03.000Z (over 1 year ago)
- Last Synced: 2025-04-03T14:46:29.759Z (about 1 year ago)
- Topics: mysql, sql
- Homepage: https://www.hackerrank.com/
- Size: 469 KB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
# **Welcome to my SQL problem-solving repository!**
This repository is dedicated to solving SQL challenges from [HackerRank](https://www.hackerrank.com/). Here, you’ll find:
- **A variety of SQL problems**: From beginner to advanced levels, covering key concepts like SELECT queries, JOINs, subqueries, window functions, and more.
- **Well-documented solutions**: Each solution includes a clear explanation of the approach and the query used to solve the problem.
- **Learning-focused insights**: Perfect for anyone looking to strengthen their SQL skills or understand different problem-solving techniques.
## Revising the Select Query I
SELECT *
FROM city
WHERE countrycode LIKE 'USA' AND population>100000;
## Revising the Select Query II
SELECT name
FROM city
WHERE countrycode LIKE 'USA' AND population>120000;
## Select All
SELECT *
FROM city;
## Select By ID
SELECT *
FROM city
WHERE id = 1661;
## Japanese Cities' Attributes
SELECT *
FROM city
WHERE countrycode LIKE 'JPN';
## Japanese Cities' Names
SELECT name
FROM city
WHERE countrycode LIKE 'JPN';
## Weather Observation Station 1
SELECT city, state
FROM station;
## Weather Observation Station 3
SELECT DISTINCT city
FROM station
WHERE id%2=0;
## Weather Observation Station 4
SELECT COUNT(city) - COUNT(DISTINCT city)
FROM station;
## Weather Observation Station 5
SELECT city, LENGTH(city)
FROM station
WHERE LENGTH(city) = (
SELECT MIN(LENGTH(city)) FROM station
)
ORDER BY city
LIMIT 1;
SELECT city, LENGTH(city)
FROM station
WHERE LENGTH(city) = (
SELECT MIN(LENGTH(city)) FROM station
)
ORDER BY city
LIMIT 1;
OR
(SELECT city, LENGTH(city) AS city_len
FROM station
ORDER BY LENGTH(city), city
LIMIT 1) UNION
(SELECT city, LENGTH(city) AS city_len
FROM station
ORDER BY LENGTH(city) DESC, city
LIMIT 1 )
## Weather Observation Station 6
SELECT DISTINCT city
FROM station
WHERE city LIKE 'a%' OR city LIKE 'e%' OR city LIKE 'i%' OR city LIKE 'o%' OR city LIKE 'u%';
## Weather Observation Station 7
SELECT DISTINCT city
FROM station
WHERE RIGHT(city, 1) IN ('a', 'e', 'i', 'o', 'u');
## Weather Observation Station 8
SELECT DISTINCT city
FROM station
WHERE LEFT(city, 1) IN ('a', 'e', 'i', 'o', 'u') AND RIGHT(city, 1) IN ('a', 'e', 'i', 'o', 'u');
## Weather Observation Station 9
SELECT DISTINCT city
FROM station
WHERE LEFT(city, 1) NOT IN ('a', 'e', 'i', 'o', 'u');
## Weather Observation Station 10
SELECT DISTINCT city
FROM station
WHERE RIGHT(city, 1) NOT IN ('a', 'e', 'i', 'o', 'u');
## Weather Observation Station 11
SELECT DISTINCT city
FROM station
WHERE LEFT(city, 1) NOT IN ('a', 'e', 'i', 'o', 'u') OR RIGHT(city, 1) NOT IN ('a', 'e', 'i', 'o', 'u');
## Weather Observation Station 12
SELECT DISTINCT city
FROM station
WHERE LEFT(city, 1) NOT IN ('a', 'e', 'i', 'o', 'u') AND RIGHT(city, 1) NOT IN ('a', 'e', 'i', 'o', 'u');
## Higher Than 75 Marks
SELECT name
FROM students
WHERE marks>75
ORDER BY RIGHT(name, 3), id;
## Employee Names
SELECT name
FROM employee
ORDER BY name;
## Employee Salaries
SELECT name
FROM employee
WHERE salary>2000 AND months<10
ORDER BY employee_id;
## Type of Triangle
SELECT
CASE
WHEN A+B>C AND B+C>A AND A+C>B THEN
CASE
WHEN A=B AND B=C AND C=A THEN "Equilateral"
WHEN A=B OR B=C OR C=A THEN "Isosceles"
ELSE "Scalene"
END
ELSE "Not A Triangle"
END
FROM triangles;