[해커랭크/SQL] 23. Revising Aggregations - The Sum Function

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

Revising Aggregations - The Sum Function | HackerRank

 

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🤔 문제 분석

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

 

💡 풀이

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