1795. Rearrange Products Table mysql

https://leetcode.com/problems/rearrange-products-table

Rearrange Products Table - LeetCode

 

select p1.product_id, 'store1' as store, store1 as price from (SELECT product_id, store1 FROM Products) p1 where store1 is not null
union
select p2.product_id, 'store2' as store, store2 as price from (SELECT product_id, store2 FROM Products) p2 where store2 is not null
union
select p3.product_id, 'store3' as store, store3 as price from (SELECT product_id, store3 FROM Products) p3 where store3 is not null

매우 구린방법으로 푼 것 같다.. 아마도 원시적인 풀이가 되기도 하면서도 조회속도도 느릴 것으로 추정