Solvesql Solution

- SQL

Author: SubAkBa

Solvesql/Solutions/count-stamps.sql

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+-- @ss.idx: 18
+-- @ss.level: 2
+-- @ss.title: 스탬프를 찍어드려요
+-- @ss.slug: count-stamps
+-- @ss.category: CASE/IF
+-- @ss.note:
+
+SELECT CASE WHEN total_bill >= 25 THEN 2
+            WHEN total_bill >= 15 THEN 1
+            ELSE 0
+       END AS stamp
+     , COUNT(*) AS count_bill
+FROM tips
+GROUP BY stamp
+ORDER BY stamp;

Solvesql/Solutions/dvdrental-vip.sql

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+-- @ss.idx: 19
+-- @ss.level: 2
+-- @ss.title: DVD 대여점 우수 고객 찾기
+-- @ss.slug: dvdrental-vip
+-- @ss.category: Subquery/CTE
+-- @ss.note:
+
+SELECT c.customer_id
+FROM customer c
+JOIN rental r ON c.customer_id = r.customer_id
+WHERE c.active = 1
+GROUP BY c.customer_id
+HAVING COUNT(c.customer_id) >= 35;

Solvesql/Solutions/summary-of-artworks-in-3-years.sql

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+-- @ss.idx: 16
+-- @ss.level: 2
+-- @ss.title: 3년간 들어온 소장품 집계하기
+-- @ss.slug: summary-of-artworks-in-3-years
+-- @ss.category: CASE/IF
+-- @ss.note: IF, CASE WHEN
+
+SELECT classification
+     , SUM(IF(YEAR(acquisition_date) = 2014, 1, 0)) AS '2014'
+     , SUM(IF(YEAR(acquisition_date) = 2015, 1, 0)) AS '2015'
+     , SUM(IF(YEAR(acquisition_date) = 2016, 1, 0)) AS '2016'
+--      , COUNT(CASE WHEN YEAR(acquisition_date) = 2014 THEN 1 END) AS '2014'
+--      , COUNT(CASE WHEN YEAR(acquisition_date) = 2015 THEN 1 END) AS '2015'
+--      , COUNT(CASE WHEN YEAR(acquisition_date) = 2016 THEN 1 END) AS '2016'
+FROM artworks
+GROUP BY classification
+ORDER BY classification;

Solvesql/Solutions/whales-of-december.sql

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+-- @ss.idx: 17
+-- @ss.level: 2
+-- @ss.title: 12월 우수 고객 찾기
+-- @ss.slug: whales-of-december
+-- @ss.category: Aggregate
+-- @ss.note:
+
+SELECT customer_id
+FROM records
+WHERE DATE_FORMAT(order_date, '%Y-%m') = '2020-12'
+GROUP BY customer_id
+HAVING SUM(sales) >= 1000;