DROP FUNCTION IF EXISTS getIncomeLevel;

DELIMITER //

CREATE FUNCTION getIncomeLevel ( monthly_value INT )
RETURNS varchar(20)

BEGIN

   DECLARE income_level varchar(20);

   IF monthly_value <= 4000 THEN
        SET income_level = 'Low Income';
   ELSEIF monthly_value > 4000 AND monthly_value <= 7000 THEN
        SET income_level = 'Avg Income';
   ELSE
        SET income_level = 'High Income';
   END IF;

   INSERT INTO log (description)
   VALUES ('getIncomeLevel function was called');

   RETURN income_level;

END; //

DELIMITER ;

SELECT getIncomeLevel(450)