[해커랭크/SQL] 24. Revising Aggregations - Averages

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

Revising Aggregations - Averages | HackerRank

---

 

🤔 문제 분석

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

 

💡 풀이

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