Question

610. Triangle Judgement

中文文档

Description

Table: Triangle

+-------------+------+
| Column Name | Type |
+-------------+------+
| x       | int  |
| y       | int  |
| z       | int  |
+-------------+------+
In SQL, (x, y, z) is the primary key column for this table.
Each row of this table contains the lengths of three line segments.

 

Report for every three line segments whether they can form a triangle.

Return the result table in any order.

The result format is in the following example.

 

Example 1:

Input: 
Triangle table:
+----+----+----+
| x  | y  | z  |
+----+----+----+
| 13 | 15 | 30 |
| 10 | 20 | 15 |
+----+----+----+
Output: 
+----+----+----+----------+
| x  | y  | z  | triangle |
+----+----+----+----------+
| 13 | 15 | 30 | No     |
| 10 | 20 | 15 | Yes    |
+----+----+----+----------+

Solutions

Solution 1: IF Statement + Triangle Inequality

The condition for whether three sides can form a triangle is that the sum of any two sides is greater than the third side. Therefore, we can use an IF statement to determine whether this condition is satisfied. If it is satisfied, we return Yes, otherwise we return No.

# Write your MySQL query statement below
SELECT
  *,
  IF(x + y > z AND x + z > y AND y + z > x, 'Yes', 'No') AS triangle
FROM Triangle;