[SQL문제풀기 - Advent of SQL 2025 🎅] 이틀 연속 미세먼지가 나빠진 날

문제

solvesql.com

https://solvesql.com/problems/bad-finddust-days-in-a-row/

내가 작성한 정답

MySQL

select a.measured_at date_alert
from measurements p
right join measurements d
on date_add(p.measured_at,interval 1 day) = d.measured_at
right join measurements a
on date_add(d.measured_at,interval 1 day) = a.measured_at
where -- (year(p.measured_at) = '2022' and year(a.measured_at) = '2022') and
    (p.pm10 < d.pm10 and d.pm10 < a.pm10) 
    and a.pm10 >= 30
order by 1;

SQLite

select a.measured_at date_alert
from measurements p
right join measurements d
on date(p.measured_at,'+1 day') = d.measured_at
right join measurements a
on date(d.measured_at,'+1 day') = a.measured_at
where -- strftime('%Y',p.measured_at) = '2022' and strftime('%Y',a.measured_at) = '2022' and
    (p.pm10 < d.pm10 and d.pm10 < a.pm10) 
    and a.pm10 >= 30
order by 1;

PostgreSQL

select a.measured_at date_alert
from measurements p
right join measurements d
on p.measured_at+1 = d.measured_at
right join measurements a
on d.measured_at+1 = a.measured_at
where -- (to_char(p.measured_at,'yyyy') = '2022' and to_char(a.measured_at,'yyyy') = '2022') and
    (p.pm10 < d.pm10 and d.pm10 < a.pm10) 
    and a.pm10 >= 30
order by 1;