Can anyone explain me this code : if-else statement in sql

To check type of triangle (i.e., Equilateral , or Isosceles or Scalene or not a triangle) A,B,C (represents sides of triangle).

Table name : Triangles

COLUMN TYPE
A   Integer
B   Integer 
C   Integer

---

select 

if(A+B+C <= 2*greatest(A,B,C),"Not A Triangle",

if(A=B and B=C,"Equilateral",

if(A=B or B=C or C=A,"Isosceles","Scalene")))

from Triangles;