HAZEL

1. Symmetric Pairs >> 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 such symmetric pairs in ascending order by the value of X. List the rows such that X1 ≤ Y1. Sample Input Sample Output 20 20 20 21 22 23 >> 문제 풀이 SELECT X , Y FROM Functions WHERE X = Y GROUP..

1. 181. Employees Earning More Than Their Managers >> 문제 The Employee table holds all employees including their managers. Every employee has an Id, and there is also a column for the manager Id. +----+-------+--------+-----------+ | Id | Name | Salary | ManagerId | +----+-------+--------+-----------+ | 1 | Joe | 70000 | 3 | | 2 | Henry | 80000 | 4 | | 3 | Sam | 60000 | NULL | | 4 | Max | 90000 |..

1. 183. Customers Who Never Order >> 문제 Suppose that a website contains two tables, the Customers table and the Orders table. Write a SQL query to find all customers who never order anything. Table: Customers. +----+-------+ | Id | Name | +----+-------+ | 1 | Joe | | 2 | Henry | | 3 | Sam | | 4 | Max | +----+-------+ Table: Orders. +----+------------+ | Id | CustomerId | +----+------------+ | 1 ..

1. African Cities >> 문제 Given the CITY and COUNTRY tables, query the names of all cities where the CONTINENT is 'Africa'. Note: CITY.CountryCode and COUNTRY.Code are matching key columns. Input Format The CITY and COUNTRY tables are described as follows: >> 문제 푼 코드 select city.NAME from city INNER JOIN COUNTRY ON CITY.CountryCode = COUNTRY.CODE WHERE COUNTRY.CONTINENT = 'Africa' www.hackerrank.c..

Top Earners >> 문제 We define an employee's total earnings to be their monthly salary x months worked, and the maximum total earnings to be the maximum total earnings for any employee in the Employee table. Write a query to find the maximum total earnings for all employees as well as the total number of employees who have maximum total earnings. Then print these values as space-separated integers...

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..