[SQL문제풀기] Revising Aggregations - The Sum Function

문제

Revising Aggregations - The Sum Function | HackerRank

Query the total population of all cities for in the District of California.

https://www.hackerrank.com/challenges/revising-aggregations-sum/problem?isFullScreen=true

MySQL, Oracle, MS SQL Server, DB2

내가 작성한 정답

select sum(population) 
from city
where district = 'California';