[SQL문제풀기] 지역별 주문의 특징

문제

solvesql.com

https://solvesql.com/problems/summary-of-artworks-in-3-years/

SQLite

내가 작성한 정답

with a as (select region, category, count(distinct order_id) c
          from records
          group by region, category),
     b as (select region, 
                  case when category = 'Furniture' then c end f,
                  case when category = 'Office Supplies' then c end os,
                  case when category = 'Technology' then c end t
            from a)
select region "Region", sum(f) "Furniture", sum(os) "Office Supplies",sum(t) "Technology"
from b
group by region;