HackerRank
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Weather Observation Station 4 MySQLHackerRank/SQL 2023. 2. 8. 17:46
문제 https://www.hackerrank.com/challenges/weather-observation-station-4/problem Weather Observation Station 4 | HackerRank Find the number of duplicate CITY names in STATION. www.hackerrank.com 풀이 집계함수 COUNT를 이용해 전체 행 수에서 중복을 제거한 행 수를 빼준다. SELECT COUNT(CITY) - COUNT(DISTINCT(CITY)) FROM STATION 참조 https://junyoung-developer.tistory.com/30 [MySQL] Weather Observation Station 4 ▶ SQL > Basic Select..