DROP FUNCTION IF EXISTS CalcularDuracaoMediaEstadias;
DELIMITER $$
CREATE FUNCTION CalcularDuracaoMediaEstadias()
RETURNS INT DETERMINISTIC
BEGIN
DECLARE duracaoMedia INT;
SELECT ROUND(AVG(DATEDIFF(data_fim, data_inicio)))
INTO duracaoMedia
FROM alugueis;
RETURN duracaoMedia;
END$$
DELIMITER ;
SELECT CalcularDuracaoMediaEstadias() AS MediaEstadia;