Triangle Judgement Problem

Problem

A pupil Tim gets homework to identify whether three line segments could possibly form a triangle.

However, this assignment is very heavy because there are hundreds of records to calculate.

Could you help Tim by writing a query to judge whether these three sides can form a triangle, assuming table triangle holds the length of the three sides x, y and z.

Examples

Table: Triangle

| x  | y  | z  |
|----|----|----|
| 13 | 15 | 30 |
| 10 | 20 | 15 |

For the sample data above, your query should return the follow result:

| x  | y  | z  | triangle |
|----|----|----|----------|
| 13 | 15 | 30 | No       |
| 10 | 20 | 15 | Yes      |

Solution

Method 1 - Simple Select and Case or if Condition

Code

Sql

Using if

SELECT *, 
    if(x+y>z AND x+z>y AND y+z>x, 'Yes', 'No') AS triangle
FROM triangle

Code

Sql

Using case: SQL CASE Expressions

SELECT *, 
    CASE
       WHEN x+y>z AND x+z>y AND y+z>x THEN 'YES'
       ELSE 'No'
    END AS triangle
FROM triangle