[HackerRank SQL] Weather Observation Station 19, 20(MySQL)

www.hackerrank.com/challenges/weather-observation-station-19/problem

Weather Observation Station 19 | HackerRank

Answer

select round(sqrt(power(max(lat_n) - min(lat_n),2) + power(max(long_w) - min(long_w),2)),4)
from station

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www.hackerrank.com/challenges/weather-observation-station-20/problem

Weather Observation Station 20 | HackerRank

Answer - 중앙값 구현하기

MySQL은 중앙값을 지원하지 않아서 따로 구현해야 한다.

set @rownum = -1;
select round(avg(lat_n),4) as median
from (select @rownum := @rownum + 1 as rownumber, lat_n
     from station
     order by lat_n) as d
where rownumber in (ceil(@rownum / 2), floor(@rownum / 2))

참고로 오라클은 중앙값 기능을 지원한다!