[HackerRank/SQL] Revising Aggregations - Averages

Problem. Revising Aggregations - Averages

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Link.

https://www.hackerrank.com/challenges/revising-aggregations-the-average-function/problem?utm_campaign=challenge-recommendation&utm_medium=email&utm_source=24-hour-campaign

Revising Aggregations - The Sum Function | HackerRank

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Description.

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

 

CITY 테이블

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Key Point. 

SELECT,

 

AVG,

 

WHERE,

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My Answer. 

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

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References.