[SQL] 해커랭크 Weather Observation Station 4

문제

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.

https://www.hackerrank.com/challenges/weather-observation-station-4/problem?isFullScreen=true

Weather Observation Station 4 | HackerRank

예시

For example, if there are three records in the table with CITY values 'New York', 'New York', 'Bengalaru', there are 2 different city names: 'New York' and 'Bengalaru'.

The query returns 1, because total number of records - number of unique city names = 3 - 2 = 1.

문제 풀이

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

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SQL을 독학하시는 분들에게 도움이 되길 바라며,

혹 더 좋은 방법이 있거나 오류가 있다면 편하게 말씀 부탁드립니다.