text: -- https://www.hackerrank.com/challenges/weather-observation-station-20/problem
  
  SELECT ROUND(r.LAT_N,4)
  FROM (SELECT ROW_NUMBER() OVER (ORDER BY LAT_N)AS row_num, 
               LAT_N
        FROM STATION
        ORDER BY LAT_N) AS r
  WHERE r.row_num = (
       SELECT CASE WHEN MAX(r.row_num) %2 =0 THEN MAX(r.row_num)/2
                   ELSE (MAX(r.row_num)+1)/2 END AS t
       FROM (SELECT ROW_NUMBER() OVER (ORDER BY LAT_N) AS row_num, 
               LAT_N
             FROM STATION) AS r
  )
  