HackerRank SQL

Type of Triangle

Problem:

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

Logic:

From the outside to the inside: SELECT IF(criteria, ‘Not A Triangle’) FROM TRIANGLES; AND THEN WORK ON THE “criteria” part by using two IF statements: IF(A=B AND B=C,’’,IF(A=B OR B=C OR A=C,’’,’’ ))

Solution:

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;

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