TriangleJudgement.sql

-- 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      |
-- +----+----+----+----------+



-- Write your PostgreSQL query statement below
-- Solution

select x,
       y,
       z,
       case when (x + y > z and 
                 y + z > x and 
                 z + x > y) then 'Yes'
        else 'No'
        end as triangle
from Triangle;