SELECTLastCoords.DEVID, Devices.EQUIPID, Devices.COMMENT, LastCoords.NAVTIME,
LastCoords.LAT, LastCoords.LONG, LastCoords.SPEED, LastCoords.SENSORS,
AD.DESCRIBTION
FROM
(select * from LastCoords INNER WHERE NAVTIME>[Введите дату начала периода] ) as LastCoords
RIGHT OUTER JOIN Devices ON LastCoords.DEVID=Devices.DEVID
WHERE LastCoords.NAVTIME is null
ORDER BY Devices.COMMENT, LastCoords.NAVTIME;
хотя not exists лучче бы.