taehyun (20230917): 데이터베이스 첫걸음 7장-8장

Document/2023/0917/taehyun/131123.sql

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+-- [ Programmers ] 즐겨찾기가 가장 많은 식당 정보 출력하기
+
+-- 중첩 서브쿼리(Nested Subquery)면서 다중열 서브쿼리(Multiple-column Subquery)인 서브쿼리를 사용한 풀이
+SELECT
+    FOOD_TYPE,
+    REST_ID,
+    REST_NAME,
+    FAVORITES
+FROM REST_INFO
+WHERE (FOOD_TYPE, FAVORITES) IN (
+    SELECT
+        FOOD_TYPE,
+        MAX(FAVORITES) AS MAXIMUM_FAVORITES
+    FROM REST_INFO
+    GROUP BY FOOD_TYPE
+)
+ORDER BY FOOD_TYPE DESC;
+

Document/2023/0917/taehyun/59413.sql

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+-- [ Programmers ] 입양 시각 구하기 (2)
+
+-- 공통 테이블 표현식(Common Table Expression, CTE)의 재귀적(Recursive) 사용을 통한 풀이
+WITH RECURSIVE cte (HOUR) AS (
+    SELECT 0 AS HOUR
+    UNION ALL
+    SELECT HOUR + 1 AS HOUR
+    FROM cte
+    WHERE HOUR < 23
+)
+
+SELECT
+    cte.HOUR AS HOUR,
+    COUNT(ANIMAL_OUTS.ANIMAL_ID) AS COUNT
+FROM cte
+LEFT JOIN ANIMAL_OUTS
+ON cte.HOUR = HOUR(ANIMAL_OUTS.DATETIME)
+GROUP BY cte.HOUR
+ORDER BY cte.HOUR ASC;

Document/2023/0917/taehyun/Dockerfile

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+FROM mysql:5.7
+
+ENV MYSQL_ROOT_PASSWORD=root
+ENV MYSQL_DATABASE=world
+
+COPY ./world.sql /docker-entrypoint-initdb.d/