Views de login logout

 CREATE VIEW v_duracao_login AS

SELECT idUsername, dataLogin, dataLogout, timestampdiff(MINUTE,dataLogin,dataLogout) AS duracao FROM tb_login JOIN tb_logout USING(idLogin);

CREATE VIEW v_login_sem_logout AS

SELECT * FROM tb_login WHERE NOT EXISTS(SELECT * FROM tb_logout WHERE tb_login.idLogin=tb_logout.idLogin);