I do not know how to do the query, being more specific I do not know how to put the group by in my query, here goes my code
objBD.query('SELECT u.ID_U, u.nombre, t.ID_T,t.tiempo, t.iteracion from USUARIO u INNER JOIN TIEMPOS t ON u.ID_U=t.ID_U GROUP BY iteracion where u.ID_U=?',[i], function(err, rows, fields) {
note: without the GROUP BY my query works well