[MySQL] Weather Observation Station 4

 

 

 

문제

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

Find the difference between the total number of CITY entries in the table and the number of distinct CITY entries in the table.

○ 총 CITY의 개수와 고유한(겹치지 않는) CITY의 개수의 차를 구하라.

 

---

풀이

SELECT  COUNT(CITY) - COUNT(DISTINCT(CITY))
  FROM  STATION;