Aggregation

Weather Observation Station 6 | HackerRank Query a list of CITY names beginning with vowels (a, e, i, o, u). www.hackerrank.com 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. -> station에서 모음(예: a, e, i, o, u)으로 시작하는 city를 중복 없이 출력하시오. Answer select distinct(city) from station where city regexp "^[aeiou]" -- ..

Weather Observation Station 5 | HackerRank Write a query to print the shortest and longest length city name along with the length of the city names. www.hackerrank.com 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 tha..

Weather Observation Station 4 | HackerRank Find the number of duplicate CITY names in STATION. www.hackerrank.com Problem Find the difference between the total number of CITY entries in the table and the number of distinct CITY entries in the table. -> station에 있는 모든 city의 수와 중복을 제외한 city의 수의 차이를 구하시오. Answer select count(city) - count(distinct(city)) from station

Weather Observation Station 3 | HackerRank Query a list of unique CITY names with even ID numbers. www.hackerrank.com 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. -> 짝수 ID 번호를 가진 city 이름을 station에서 query 하시오. 결과를 임의의 순서로 출력하지만 중복은 답변에서 제외하시오. Answer select distinct(city) from statio..

Weather Observation Station 2 | HackerRank Write a query to print the sum of LAT_N and the sum of LONG_W separated by space, rounded to 2 decimal places. www.hackerrank.com Problem 1. The sum of all values in LAT_N rounded to a scale of 2 decimal places. ->LAT_N의 모든 값의 합은 소수점 2자리 척도로 반올림하시오. 2. The sum of all values in LONG_W rounded to a scale of 2 decimal places. ->LONG_W의 모든 값의 합은 소수점 2자리 척도로..

Weather Observation Station 1 | HackerRank Write a query to print the CITY and STATE for each attribute in the STATION table. www.hackerrank.com Problem Query a list of CITY and STATE from the STATION table. -> Station 테이블에서 City 및 State 컬럼을 출력. Answer select city,state from station