#97. [LeetCode / MySQL] 2356. Number of Unique Subjects Taught by Each Teacher

문제 입력 코드 SELECT teacher_id, COUNT(DISTINCT(subject_id)) AS cnt FROM Teacher GROUP BY teacher_id; 코드 설명 #SELECT #COUNT #DISTINCT #GROUP BY 문제 출처 LeetCode - The World's Leading Online Programming Learning Platform Level up your coding skills and quickly land a job. This is the best place to expand your knowledge and get prepared for your next interview. leetcode.com

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• · 2023. 9. 23.
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#96. [LeetCode / MySQL] 550. Game Play Analysis IV

문제 입력 코드 SELECT ROUND(COUNT(DISTINCT player_id)/(SELECT COUNT(DISTINCT player_id) FROM Activity), 2) AS fraction FROM Activity WHERE (player_id, DATE_SUB(event_date, INTERVAL 1 DAY)) IN ( SELECT player_id, MIN(event_date) AS first_login FROM Activity GROUP BY player_id ) 코드 설명 #SELECT #ROUND #COUNT #DISTINCT #DATE_SUB #INTERVAL #MIN #GROUP BY 문제 출처 Game Play Analysis IV - LeetCode Can you solve ..

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• · 2023. 9. 22.
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#95. [LeetCode / MySQL] 1174. Immediate Food Delivery II

문제 입력 코드 SELECT ROUND(AVG(order_date = customer_pref_delivery_date) * 100, 2) AS immediate_percentage FROM Delivery WHERE (customer_id, order_date) IN ( SELECT customer_id, MIN(order_date) FROM Delivery GROUP BY customer_id ) 코드 설명 #SELECT #ROUND #AVG #MIN #GROUP BY #SUBQUERY 문제 출처 Immediate Food Delivery II - LeetCode Can you solve this real interview question? Immediate Food Delivery II - Tabl..

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• · 2023. 9. 21.
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#94. [LeetCode / MySQL] 1193. Monthly Transactions I

문제 입력 코드 1. SELECT DATE_FORMAT(trans_date, '%Y-%m') AS month, country, COUNT(*) AS trans_count, SUM(IF(state='approved', 1, 0)) AS approved_count, SUM(amount) AS trans_total_amount, SUM(IF(state='approved', amount, 0)) AS approved_total_amount FROM Transactions GROUP BY month, country 2. SELECT SUBSTR(trans_date, 1, 7) AS month, country, COUNT(*) AS trans_count, SUM(CASE WHEN state = 'approved' ..

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• · 2023. 9. 20.
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#93. [LeetCode / MySQL] 1211. Queries Quality and Percentage

문제 입력 코드 1. IF SELECT query_name, ROUND(AVG(rating/position), 2) AS quality, ROUND(AVG(IF(rating < 3, 1, 0))*100, 2) AS poor_query_percentage FROM Queries GROUP BY query_name 2. CASE WHEN SELECT query_name, ROUND(AVG(rating/position), 2) AS quality, ROUND(SUM( CASE WHEN rating < 3 THEN 1 ELSE 0 END ) * 100 / COUNT(*), 2) AS poor_query_percentage FROM Queries GROUP BY query_name 코드 설명 #SELECT #RO..

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• · 2023. 9. 19.
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#92. [LeetCode / MySQL] 1633. Percentage of Users Attended a Contest

문제 입력 코드 SELECT contest_id, ROUND(COUNT(DISTINCT user_id)/(SELECT COUNT(user_id) FROM Users) * 100, 2) AS percentage FROM Register GROUP BY contest_id ORDER BY percentage DESC, contest_id ASC; 코드 설명 #SELECT #ROUND #COUNT #DISTINCT #GROUP BY #ORDER BY 문제 출처 Percentage of Users Attended a Contest - LeetCode Can you solve this real interview question? Percentage of Users Attended a Contest - Table:..

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• · 2023. 9. 18.
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