노선별 평균 역 사이 거리 조회하기

SELECT ROUTE,	
CONCAT(ROUND(SUM(D_BETWEEN_DIST), 1), 'km') AS TOTAL_DISTANCE,
CONCAT(ROUND(AVG(D_BETWEEN_DIST), 2), 'km') AS AVERAGE_DISTANCE
FROM SUBWAY_DISTANCE 
GROUP BY ROUTE
ORDER BY SUM(D_BETWEEN_DIST) DESC;

- CONCAT을 썼기 때문에 내림차순 정렬할 때 CONCAT을 쓴 상태를 가져다 정렬하면 안된다.