• + 5 comments

    select
    case when a+b<=c or b+c<=a or a+c<=b then 'Not A Triangle' when a=b and b=c and c=a then 'Equilateral' when a=b or b=c or a=c then 'Isosceles'

    else 'Scalene' end from TRIANGLES ;

    first check for not a triangle condition, it worked for me...