leetcode_gym/_problems/sql_triangles.md

layout, title, last_solved, category, leetcode_url, status

layout	title	last_solved	category	leetcode_url	status
page	Triangles (SQL Case Statements)		sql	https://www.hackerrank.com/challenges/what-type-of-triangle/problem	Attempted

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
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 .

Solution

{% highlight sql %}

select A,B,C,

case when A=B and B=C and C=A then 'Equilateral' when A=B or B=C or C=A then 'Isosceles' when A!=B and B!=C and C!=A and (A+B>C and B+C>A and A+C>A) then 'Scalene' else 'Not A Triangle' end

from triangles

{% endhighlight %}

---

This is the right answer (just take away the A,B,C)

{% highlight sql %}

select A,B,C,

case when A+B>C and B+C>A and A+C>A then

case when A=B and B=C and C=A then 'Equilateral'
     when A=B or B=C or C=A then 'Isosceles'
     else 'Scalene'
     end

else 'Not A Triangle' end

from triangles

{% endhighlight %}