Type of Triangle (CASE WHEN/ THEN)

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.

 

Sample Input

 

Sample Output

Isosceles
Equilateral
Scalene
Not A Triangle

 

Explanation

Values in the tuple  form an Isosceles triangle, because .
Values in the tuple  form an Equilateral triangle, because . Values in the tuple  form a Scalene triangle, because .
Values in the tuple  cannot form a triangle because the combined value of sides  and  is not larger than that of side .

 

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[나의 풀이]

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

 

출력결과

A

Equilateral

Equilateral

Isosceles

Equilateral

Isosceles

Equilateral

Not A Triangle

Scalene

Scalene

: :

 

 

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[설명]

CASE WHEN 은 파이썬에서 IF문과 같다.

 

SQL 문	설명
WHEN A = B AND B = C THEN 'Equilateral'	세 변의 길이가 같으면 'Equilateral' 출력
WHEN A = B OR B = C OR A = C THEN 'Isosceles'	두 변의 길이가 같으면 'Isosceles' 출력
WHEN A+B <= C OR A+C <= B OR B+C <= A THEN 'Not A Triangle'	두 변의 길이의 합이 다른 한 변보다 짧으면 'Not A Triangle' 출력
ELSE 'Scalene' END	위의 조건들이 다 아니라면 'Scalene' 출력