[MySQL] Hackerrank SQL 연습문제 (1)

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SQL Übung - Hackerrank

• SQL 문제 풀이를 통한 SQL 연습

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Revising the Select Query I

• 10/11/2021

SELECT *
FROM city
WHERE countrycode="USA"
AND population > 100000

Revising the Select Query II

• 10/11/2021

SELECT name
FROM city
WHERE population > 120000
AND countrycode="USA";

Select All

• 10/11/2021

SELECT *
FROM city;

Select By ID

• 10/11/2021

SELECT *
FROM city
WHERE id = 1661;

Japanese Cities’ Attributes

• 11/11/2021

SELECT *
FROM city
WHERE countrycode = 'JPN';

Japanese Cities’ Names

• 11/11/2021

SELECT name
FROM city
WHERE countrycode = 'JPN'

Weather Observation Station 1

• 11/11/2021

SELECT city, state
FROM station;

Weather Observation Station 3

• 11/11/2021

SELECT DISTINCT(city)
FROM station
WHERE ID % 2 = 0;

Weather Observation Station 4

• 11/11/2021

SELECT COUNT(*) - COUNT(DISTINCT(city))
FROM station;

Weather Observation Station 5

• 11/11/2021

(SELECT city, LENGTH(city)
FROM station
ORDER BY LENGTH(city) ASC, city
LIMIT 1)
UNION
(SELECT city, LENGTH(city)
FROM station
ORDER BY LENGTH(city) DESC, city
LIMIT 1)