HAZEL

>> 문제 Write an SQL query to report the nth highest salary from the Employee table. If there is no nth highest salary, the query should report null. ex, 4번째로 높은 셀러리가 없을 경우 null 을 나온다 The query result format is in the following example. 동점인 점수는 다 1등 그 다음은 2등으로, dense rank 를 기준으로 생각해주면 된다. https://leetcode.com/problems/nth-highest-salary/submissions/ >> 문제 풀이 방법 * 사용자 정의 함수의 방법 https://hazel01.tist..

The Report >> 문제 You are given two tables: Students and Grades. Students contains three columns ID, Name and Marks. Grades contains the following data: Ketty gives Eve a task to generate a report containing three columns: Name, Grade and Mark. Ketty doesn't want the NAMES of those students who received a grade lower than 8. The report must be in descending order by grade -- i.e. higher grades ar..

Challenges >> 문제 Julia asked her students to create some coding challenges. Write a query to print the hacker_id, name, and the total number of challenges created by each student. Sort your results by the total number of challenges in descending order. If more than one student created the same number of challenges, then sort the result by hacker_id. If more than one student created the same numb..

184. Department Highest Salary >> 문제 The Employee table holds all employees. Every employee has an Id, a salary, and there is also a column for the department Id. +----+-------+--------+--------------+ | Id | Name | Salary | DepartmentId | +----+-------+--------+--------------+ | 1 | Joe | 70000 | 1 | | 2 | Jim | 90000 | 1 | | 3 | Henry | 80000 | 2 | | 4 | Sam | 60000 | 2 | | 5 | Max | 90000 | 1..

196. Delete Duplicate Emails >> 문제 Write a SQL query to delete all duplicate email entries in a table named Person, keeping only unique emails based on its smallest Id. +----+------------------+ | Id | Email | +----+------------------+ | 1 | john@example.com | | 2 | bob@example.com | | 3 | john@example.com | +----+------------------+ Id is the primary key column for this table. For example, afte..

627. Swap Salary >> 문제 +-------------+----------+ | Column Name | Type | +-------------+----------+ | id | int | | name | varchar | | sex | ENUM | | salary | int | +-------------+----------+ id is the primary key for this table. The sex column is ENUM value of type ('m', 'f'). The table contains information about an employee. Write an SQL query to swap all 'f' and 'm' values (i.e., change all 'f..

1. Type of Triangle >> 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 sides of equal length. Isosceles: It's a triangle with sides of equal length. Scalene: It's a triangle with sides of differing lengths. Not A Triangle: The given valu..