[hackerrank] Revising Aggregations - Averages

[hackerrank] Prepare > SQL > Aggregation > Revising Aggregations - Averages

 

[문제]

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

Input Format

The CITY table is described as follows: 

 

[MYSQL]

 

 

[ORCALE]

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