출처 : 전국 카페 주소 데이터 정제하기 SolveSQL
내 답안
WITH cafe_prep AS (SELECT name
, address
, SUBSTRING_INDEX(address, ' ', 1) AS sido
, SUBSTRING_INDEX(address, ' ', 2) AS sigungu_prep
FROM cafes)
SELECT sido
, SUBSTRING_INDEX(sigungu_prep, ' ', -1) AS sigungu
, COUNT(*) AS cnt
FROM cafe_prep
GROUP BY sido, sigungu
ORDER BY cnt DESC;