[SQL문제풀기 - Advent of SQL 2025 🎅] 12월 우수 고객 찾기

문제

solvesql.com

https://solvesql.com/problems/whales-of-december/

내가 작성한 정답

공통

select customer_id
from records
where order_date between '2020-12-01' and '2021-01-01'
group by customer_id
having sum(sales) >= 1000;

날짜 변환 메서드 다름

// MySQL 
select customer_id
from records
where date_format(order_date,'%Y%m') = '202012'
group by customer_id
having sum(sales) >= 1000;

// PostgreSQL
select customer_id
from records
where to_char(order_date,'yymm') = '2012' 
group by customer_id
having sum(sales) >= 1000;

// SQLite
select customer_id
from records
where strftime('%Y-%m',order_date) = '2020-12' 
group by customer_id
having sum(sales) >= 1000;