[SQL문제풀기] 배송 예정일 예측 성공과 실패

문제

solvesql.com

https://solvesql.com/problems/estimated-delivery-date/

SQLite

내가 작성한 정답

select strftime('%Y-%m-%d',order_purchase_timestamp) purchase_date, 
        sum(case when order_delivered_customer_date <= order_estimated_delivery_date then 1 else 0 end) success,
        sum(case when order_delivered_customer_date > order_estimated_delivery_date then 1 else 0 end) fail
from olist_orders_dataset 
where strftime('%Y%m',purchase_date) = '201701' 
group by purchase_date;