[SQL][HackerRank] Population Density Difference

https://www.hackerrank.com/challenges/population-density-difference/problem?h_r=next-challenge&h_v=zen

Population Density Difference | HackerRank

Query the difference between the maximum and minimum populations in CITY.

Input Format

The CITY table is described as follows:

SELECT MAX(POPULATION) - MIN(POPULATION)
FROM CITY;