Milky's note

https://www.hackerrank.com/challenges/revising-aggregations-the-average-function/problem?isFullScreen=true Revising Aggregations - Averages | HackerRank Query the average population of all cities in the District of California. www.hackerrank.com [문제] Query the average population of all cities in CITY where District is California. Input Format The CITY table is described as follows: [답] -mysql se..