[HackerRank] Revising Aggregations- Averages (MySQL)

https://www.hackerrank.com/challenges/revising-aggregations-the-average-function/problem?isFullScreen=true&h_r=next-challenge&h_v=zen&h_r=next-challenge&h_v=zen 

Revising Aggregations - Averages | HackerRank

 

문제

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

Input Format

The CITY table is described as follows: 

풀이

select avg(population)
from city
where district = 'California'