SQL 문제풀이

[해커랭크 SQL] Basic Select - Weather Observation Station 4

냄비짱 2023. 8. 16. 00:21
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❓ Question

https://www.hackerrank.com/challenges/weather-observation-station-4

 

Weather Observation Station 4 | HackerRank

Find the number of duplicate CITY names in STATION.

www.hackerrank.com

❗ Answer

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

📌 Discussion

- COUNT로 레코드의 개수를 집계