/* MS SERVER ( GUYS FIRST FIND WHAT NOT A TRAINGLE THEN Isosceles CAUSE IF A=B IS CORRECT THEN Isosceles BUT A+B = C THEN ITS NOT A TRAINGLE SO LET SERVER CHECK FIRST IF A+B <= C THEN A=B */
SELECT CASE WHEN A=B AND B=C AND C=A THEN 'Equilateral' WHEN A+B<=C OR B+C<=A OR C+A<=B THEN 'Not A Triangle' WHEN A=B OR B=C OR C=A THEN 'Isosceles' ELSE 'Scalene' END FROM TRIANGLES

QUERY.............

SELECT CASE WHEN A + B > C AND A + C > B AND B + C > A THEN CASE WHEN A = B AND B = C THEN 'Equilateral' WHEN A = B OR B = C OR A = C THEN 'Isosceles' ELSE 'Scalene' END ELSE 'Not A Triangle' END FROM TRIANGLES;

I don't understand why you'd have a check for 'Not A Triangle' if only 3 columns. Is this in the case that there are NULL or '0' values for one of the columns?

what is wrong here?

SELECT 'Equilateral' FROM TRIANGLES WHERE (A=B AND B=C); SELECT 'Iscosceles' FROM TRIANGLES WHERE (A=B OR B=C OR C=A) AND (A+B>C AND A+C>B AND B+C>A); SELECT 'Scalene' FROM TRIANGLES WHERE (A<>B AND B<>C AND C<>A) AND (A+B>C AND A+C>B AND B+C>A); SELECT 'Not a Triangle' FROM TRIANGLES WHERE (A+B<=C OR A+C<=B OR B+C<=A);

For MySQL Platform

SELECT
    CASE
        WHEN a+b <= c OR b+c <= a OR c+a <= b THEN "Not A Triangle"
        WHEN a = b AND b = c THEN  "Equilateral"
        WHEN a = b OR b = c OR c = a THEN "Isosceles"
        ELSE " Scalene"
    END AS type_of_triangle
FROM triangles;