[MySQL/HackerRank] Type of Triangle

https://www.hackerrank.com/challenges/what-type-of-triangle/problem?isFullScreen=true 

Type of Triangle | HackerRank

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 values of A, B, and C don't form a triangle.

Input Format

The TRIANGLES table is described as follows:

Each row in the table denotes the lengths of each of a triangle's three sides.

Code

SELECT CASE
        WHEN A = B AND B = C THEN 'Equilateral'
        WHEN A + B <= C OR A + C <= B OR B + C <= A THEN 'Not A Triangle'
        WHEN A = B OR A = C OR B = C THEN 'Isosceles'
        ELSE 'Scalene' END
FROM TRIANGLES;