ror_coding

MySQL에선 select 구문의 alias를 group by 에서 쓸 수 있다 ! Question We define an employee's total earnings to be their monthly 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 s..

Question You are given three tables: Students, Friends and Packages. Students contains two columns: ID and Name. Friends contains two columns: ID and Friend_ID (ID of the ONLY best friend). Packages contains two columns: ID and Salary (offered salary in $ thousands per month).Write a query to output the names of those students whose best friends got offered a higher salary than them. Names must ..

Question 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 are entered ..

삼각형이 되기 위한 세 변의 조건. Question 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 va..

20 20이 self join하는 예외 케이스 나눠서 풀기 ! QuestionYou 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 InputSample Output20 2020 2122 23 Point 20 20이 하나만 있을 때 서로 self join해서 20 20 ..

WITH RECURSIVE (CTE) 로 Level 구하기 !!! 매우 중요! Question You are given a table, BST, containing two columns: N and P, where N represents the value of a node in Binary Tree, and P is the parent of N.Write a query to find the node type of Binary Tree ordered by the value of the node. Output one of the following for each node:Root: If node is root node.Leaf: If node is leaf node.Inner: If node is neith..