뉴에이지의 DATABASE

DATA SCIENCE/SQL

문제 https://www.hackerrank.com/challenges/weather-observation-station-8/problem Query the list of CITY names from STATION which have vowels (i.e., a, e, i, o, and u) as both their first and last characters. Your result cannot contain duplicates. Input Format The STATION table is described as follows: where LAT_N is the northern latitude and LONG_W is the western longitude. 풀이 1) vowels(모음) 으로 시작하..

2021. 12. 21.

DATA SCIENCE/SQL

문제 https://www.hackerrank.com/challenges/weather-observation-station-7 Query the list of CITY names ending with vowels (a, e, i, o, u) from STATION. Your result cannot contain duplicates. Input Format The STATION table is described as follows: where LAT_N is the northern latitude and LONG_W is the western longitude. 풀이 1) vowels(모음) 으로 끝나는 city name 리스트 중 2) 중복 없는 unique한 값 위 두 조건을 만족하는 데이터를 추출하..

2021. 12. 21.

DATA SCIENCE/SQL

문제 https://www.hackerrank.com/challenges/weather-observation-station-6/problem Query the list of CITY names starting with vowels (i.e., a, e, i, o, or u) from STATION. Your result cannot contain duplicates. Input Format The STATION table is described as follows: where LAT_N is the northern latitude and LONG_W is the western longitude. 풀이 1) vowels(모음) 으로 시작하는 city name 리스트 중 2) 중복 없는 unique한 값 위..

2021. 12. 21.

DATA SCIENCE/SQL

문제 https://www.hackerrank.com/challenges/weather-observation-station-5/problem Query the two cities in STATION with the shortest and longest CITY names, as well as their respective lengths (i.e.: number of characters in the name). If there is more than one smallest or largest city, choose the one that comes first when ordered alphabetically. The STATION table is described as follows: where LAT_N..

2021. 12. 21.

DATA SCIENCE/SQL

문제 https://www.hackerrank.com/challenges/weather-observation-station-4/problem Find the difference between the total number of CITY entries in the table and the number of distinct CITY entries in the table. The STATION table is described as follows: where LAT_N is the northern latitude and LONG_W is the western longitude. For example, if there are three records in the table with CITY values 'New..

2021. 12. 21.

DATA SCIENCE/SQL

문제 https://www.hackerrank.com/challenges/weather-observation-station-3/problem Query a list of CITY names from STATION for cities that have an even ID number. Print the results in any order, but exclude duplicates from the answer. The STATION table is described as follows: where LAT_N is the northern latitude and LONG_W is the western longitude. 풀이 1) ID number가 even(짝수)인 경우에 city와 station을 출력하라..

2021. 12. 21.

DATA SCIENCE/SQL

문제 https://www.hackerrank.com/challenges/weather-observation-station-2/problem Query the following two values from the STATION table: The sum of all values in LAT_N rounded to a scale of 2 decimal places. The sum of all values in LONG_W rounded to a scale of 2 decimal places. Input Format The STATION table is described as follows: where LAT_N is the northern latitude and LONG_W is the western lo..

2021. 12. 21.

DATA SCIENCE/SQL

문제 https://www.hackerrank.com/challenges/weather-observation-station-1/problem Query a list of CITY and STATE from the STATION table. The STATION table is described as follows: where LAT_N is the northern latitude and LONG_W is the western longitude. 풀이 단순히 테이블에서 city와 state를 가져오면 된다. Language: MySQL select city, state from station

2021. 12. 21.

DATA SCIENCE/SQL

문제 https://www.hackerrank.com/challenges/japanese-cities-name/problem Query the names of all the Japanese cities in the CITY table. The COUNTRYCODE for Japan is JPN. The CITY table is described as follows: 풀이 1) countrycode가 'JPN'인 모든 name 목록을 출력하면 되는 간단한 문제이다. Language: MySQL select name from city where countrycode like 'JPN'

2021. 12. 21.

DATA SCIENCE/SQL

문제 https://www.hackerrank.com/challenges/japanese-cities-attributes/problem Query all attributes of every Japanese city in the CITY table. The COUNTRYCODE for Japan is JPN. The CITY table is described as follows: 풀이 1) countrycode가 'JPN'인 모든 컬럼을 출력하면 되는 간단한 문제이다. Language: MySQL select * from city where countrycode like 'JPN'

2021. 12. 21.

DATA SCIENCE/SQL

문제 https://www.hackerrank.com/challenges/select-by-id/problem Query all columns for a city in CITY with the ID 1661. The CITY table is described as follows: 풀이 1) ID가 1661인 모든 컬럼을 출력하면 되는 간단한 문제이다. Language: MySQL select * from city where id = 1661

2021. 12. 21.

DATA SCIENCE/SQL

문제 https://www.hackerrank.com/challenges/select-all-sql/problem Query all columns (attributes) for every row in the CITY table. The CITY table is described as follows: 풀이 위 테이블에 있는 모든 columns, rows를 출력하면 되는 문제이다. '*' 활용법을 설명하는 간단한 문제로 보인다. Language: MYSQL select * from city

2021. 12. 21.