[해커랭크 SQL] Aggregation - Revising Aggregations - The Sum Function

❓ Question
https://www.hackerrank.com/challenges/revising-aggregations-sum

Revising Aggregations - The Sum Function | HackerRank

 

❗ Answer

SELECT SUM(population)
    FROM city
    WHERE district='California';

📌 Discussion

• where로 조건에 맞는 레코드 불러온 후 sum으로 집계