오늘도 배운다

인생은 실수와 우연으로 덮여있다. 실수는 실패가 아니다. 실수의 결과는 아무도 모른다. 왜냐하면, 실수 뒤엔 항상 우연이라는 것이 따라오기 때문이다. 우연이 무슨 짓을 저질러줄지는 아무도 모른다. 실수를 성공으로 바꿔줄지도 모르고, 완벽한 계획을 뿌리부터 틀어지게 만들어버릴지도 모른다. , 아르투어 쇼펜하우어 지음 / 김옥 편역 - 밀리의 서재 https://www.millie.co.kr/v3/bookDetail/179612096 쇼펜하우어는 다윗왕의 삶을 소개한다. 부하의 아내를 사랑했기에 그를 전쟁에 앞세워 죽게하고 그의 아내를 얻었다. 그러나 신은 노했고 사이에 난 자식을 죽였다. 이후, 다윗은 그 자신을 평생 혐오하지 않았고, 자식을 죽인 신을 찬양하며 그의 인생을 열심히 살아갔다. 내 자신이 결..

문제 source: LeetCode Write an SQL query to: - Find the name of the user who has rated the greatest number of movies. In case of a tie, return the lexicographically smaller user name. - Find the movie name with the highest average rating in February 2020. In case of a tie, return the lexicographically smaller movie name. 제출답안(MS SQL Server) WITH rating_count_by_user AS (SELECT user_id, COUNT(ratin..

문제 source: LeetCode Write an SQL query to report the number of bank accounts of each salary category. The salary categories are: "Low Salary": All the salaries strictly less than $20000."Average Salary": All the salaries in the inclusive range [$20000, $50000]."High Salary": All the salaries strictly greater than $50000. The result table must contain all three categories. If there are no account..

문제 source: LeetCode The confirmation rate of a user is the number of 'confirmed' messages divided by the total number of requested confirmation messages. The confirmation rate of a user that did not request any confirmation messages is 0. Round the confirmation rate to two decimal places. Write an SQL query to find the confirmation rate of each user. Return the result table in any order. 제출답안(MS..

문제 source: LeetCode You are the restaurant owner and you want to analyze a possible expansion (there will be at least one customer every day). Write an SQL query to compute the moving average of how much the customer paid in a seven days window (i.e., current day + 6 days before). average_amount should be rounded to two decimal places. Return result table ordered by visited_on in ascending order..

문제 source: LeetCode There is a queue of people waiting to board a bus. However, the bus has a weight limit of 1000 kilograms, so there may be some people who cannot board. Write an SQL query to find the person_name of the last person that can fit on the bus without exceeding the weight limit. The test cases are generated such that the first person does not exceed the weight limit. 제출답안(MS SQL Se..

문제 source: LeetCode Write an SQL query to report the fraction of players that logged in again on the day after the day they first logged in, rounded to 2 decimal places. In other words, you need to count the number of players that logged in for at least two consecutive days starting from their first login date, then divide that number by the total number of players. 제출답안(MS SQL Server) WITH log_..