[해커랭크] Revising Aggregations - Averages

문제링크 : https://www.hackerrank.com/challenges/revising-aggregations-the-average-function/problem?isFullScreen=true

 

❓문제

Query the average population of all cities in CITY where District is California.

Input Format

The CITY table is described as follows: 

 

🔉 문제 설명

지역구가 California인 CITY의 인구 평균을 쿼

 

❗답

SELECT AVG(POPULATION)
FROM CITY
WHERE DISTRICT = 'California'

 

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🤔풀이

 AVG : 평균