[MySQL/HackerRank] Weather Observation Station 20

https://www.hackerrank.com/challenges/weather-observation-station-20/problem?isFullScreen=true 

Weather Observation Station 20 | HackerRank

문제

A median is defined as a number separating the higher half of a data set from the lower half. Query the median of the Northern Latitudes (LAT_N) from STATION and round your answer to  decimal places.

Input Format

The STATION table is described as follows:

where LAT_N is the northern latitude and LONG_W is the western longitude.

Code

SELECT ROUND(LAT_N, 4)
FROM (SELECT LAT_N, PERCENT_RANK() OVER (ORDER BY LAT_N) AS R FROM STATION) AS S
WHERE S.R=0.5