관재탑

https://www.hackerrank.com/challenges/symmetric-pairs/problem?isFullScreen=true Symmetric Pairs | HackerRank Write a query to output all symmetric pairs in ascending order by the value of X. www.hackerrank.com 문제 You are given a table, Functions, containing two columns: X and Y. Two pairs (X1, Y1) and (X2, Y2) are said to be symmetric pairs if X1 = Y2 and X2 = Y1. Write a query to output all suc..

SQL/MySQL 문제풀이 2022. 7. 20. 16:40

https://leetcode.com/problems/rising-temperature/ Rising Temperature - LeetCode 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 문제 Table: Weather +---------------+---------+ | Column Name | Type | +---------------+---------+ | id | int | | recordDate | date | | temperature | int | +--------..

SQL/MySQL 문제풀이 2022. 7. 20. 15:31

https://leetcode.com/problems/employees-earning-more-than-their-managers/ Employees Earning More Than Their Managers - LeetCode 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 문제 Table: Employee +-------------+---------+ | Column Name | Type | +-------------+---------+ | id | int | | name |..

SQL/MySQL 문제풀이 2022. 7. 20. 14:19

https://leetcode.com/problems/customers-who-never-order/submissions/ Customers Who Never Order - LeetCode 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 문제 table: Customers +-------------+---------+ | Column Name | Type | +-------------+---------+ | id | int | | name | varchar | +---------..

SQL/MySQL 문제풀이 2022. 7. 20. 13:31

https://leetcode.com/problems/reformat-department-table/ Reformat Department Table - LeetCode 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 문제 +-------------+---------+ | Column Name | Type | +-------------+---------+ | id | int | | revenue | int | | month | varchar | +-------------+-----..

SQL/MySQL 문제풀이 2022. 7. 20. 11:04

https://www.hackerrank.com/challenges/what-type-of-triangle/problem?isFullScreen=true Type of Triangle | HackerRank Query a triangle's type based on its side lengths. www.hackerrank.com 문제 Write a query identifying the type of each record in the TRIANGLES table using its three side lengths. Output one of the following statements for each record in the table: Equilateral: It's a triangle with sid..

SQL/MySQL 문제풀이 2022. 7. 18. 19:58

https://www.hackerrank.com/challenges/earnings-of-employees/problem?isFullScreen=true Top Earners | HackerRank Find the maximum amount of money earned by any employee, as well as the number of top earners (people who have earned this amount). www.hackerrank.com 문제 We define an employee's total earnings to be their monthly worked, and the maximum total earnings to be the maximum total earnings fo..

SQL/MySQL 문제풀이 2022. 7. 18. 18:53

1.집계함수 1-1. COUNT() : 컬럼의 개수를 세준다. 1-2. AVG() : 컬럼이 평균을 구해준다. 1-3. SUM(), MAX(), MIN()의 함수도 있다. 2. GROUP BY, HAVING WHERE은 GROUP BY위에 HAVING은 밑에 적어준다. WHERE은 GROUP BY에 들어가기 전에 필터를 걸어준다. HAVING은 GROUP BY로 나온 결과에 필터를 걸어준다. SELECT SupplierID, CategoryID, ROUND(AVG(Price)) FROM Products WHERE Price >= 20 GROUP BY SupplierID, CategoryID HAVING ROUND(AVG(Price)) >= 40 ORDER BY ROUND(AVG(Price)) DESC G..

SQL/MySQL 이론 2022. 7. 18. 17:06