V 25일차 - JDBC와 DBMS, SQLyog_04 문제풀이

프로그래머스 SQL 고득점 kit = https://school.programmers.co.kr/learn/courses/30/parts/17042

꾸준히 풀것!

#4. 가장 많이 주문한 사람의 아이디와 이름, 주문개수는? ???
SELECT u.userId AS '아이디', u.userName AS '이름', COUNT() AS '주문갯수'
FROM t_order AS o
INNER JOIN t_user AS u
ON o.userNo = u.id
INNER JOIN t_product AS p
ON o.productNo = p.id
GROUP BY u.id
ORDER BY COUNT() DESC LIMIT 1;

#5. 소지섭이 사용한 총 금액은? ???
SELECT SUM(price) AS '소지섭이 사용한 총 금액'
FROM t_order AS o
INNER JOIN t_user AS u
ON o.userNo = u.id
INNER JOIN t_product AS p
ON o.productNo = p.id
WHERE u.userName = '소지섭';

SELECT * FROM t_user
WHERE userName = '소지섭';

SELECT * FROM t_order;

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