[SQL][HackerRank] Type of Triangle

https://www.hackerrank.com/challenges/what-type-of-triangle/problem

Type of Triangle | HackerRank

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 3 sides of equal length.
• Isosceles: It's a triangle with 2 sides of equal length.
• Scalene: It's a triangle with 3 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.

Sample Input

Sample Output

Isosceles

Equilateral

Scalene

Not A Triangle

SELECT IF(A+B>C AND A+C>B AND B+C>A, IF(A=B AND B=C, 'Equilateral', IF(A=B OR B=C OR A=C, 'Isosceles', 'Scalene')), 'Not A Triangle') 
FROM TRIANGLES;

‘IF(condition, A, B)’

TRUE 면 A 아니면 B