CREATE FUNCTION "TriangleNumber" (IN "N" INTEGER)
RETURNS INTEGER
BEGIN   
 DECLARE Result, I INTEGER;
 
 SET I = N;     -- Required
 CASE I
   WHEN 0 THEN
     SET Result = 0;
   WHEN 1 THEN
     SET result = 1;
   ELSE
     SET Result = I + TriangleNumber(I - 1);
 END CASE;
  
 RETURN Result;
END