[SQL문제풀기 - Advent of SQL 2025] 서울숲에 놀러 가기 좋은 날

문제

solvesql.com

https://solvesql.com/problems/good-days-for-a-seoulforest-picnic/

내가 작성한 정답

3개 공통

select measured_at good_day
from measurements
where measured_at between '2022-12-01' and '2023-01-01'
  and pm2_5 <= 9
order by 1;

MySQL

select measured_at good_day
from measurements
where date_format(measured_at,'%y%m') = '2212'
and pm2_5 <= 9
order by 1;

SQLite

select measured_at good_day
from measurements
where strftime('%Y%m',measured_at) ='202212'
  and pm2_5 <= 9
order by 1;

PostgreSQL

select measured_at good_day
from measurements
where to_char(measured_at,'yymm') = '2212'
  and pm2_5 <= 9
order by 1;