[SQL문제풀기 - Advent of SQL 2025 🎅] 스탬프를 찍어드려요

문제

solvesql.com

https://solvesql.com/problems/count-stamps/

내가 작성한 정답

MySQL

select stamp, count(*) count_bill
from (select case when total_bill >= 25 then 2 
          when total_bill >= 15 then 1 
          else 0 end stamp
      from tips) st
group by stamp
order by 1;

MySQL, PostgreSQL

select stamp, count(*) count_bill
from (select case when total_bill >= 25 then 2 
          when total_bill >= 15 then 1 
          else 0 end stamp
      from tips)
group by stamp
order by 1;