如果在Select语句中使用Alias，则指定SELECT DISTINCT时，ORDER BY项必须出现在选择列表中

Question

直到最近，以下SQL语句在使用MSSQL数据库时没有任何问题：

SELECT DISTINCT Flights.MODEL_ID,
                Pilots.NAME,
                Models.DESCRIPTION,
                Flights.KURSLAENGE * 4828 * Flights.DREIECKE + Flights.SPEED AS POINTS,
                Flights.SPEED,
                Flights.DREIECKE * Flights.KURSLAENGE * 0.0048284            AS DISTANZ,
                Flights.FLIGHT_ID,
                Pilots.PILOT_ID,
                Flights.STARTZEIT,
                Flights.DREIECKE,
                Flights.CATEGORY_ID,
                Pilots.VORNAME,
                Flights.KURSLAENGE,
                Flights.PLACE_ID
FROM   Flights
       INNER JOIN Models
         ON Flights.MODEL_ID = Models.MODEL_ID
       INNER JOIN Pilots
         ON Models.PILOT_ID = Pilots.PILOT_ID
WHERE  ( Flights.STARTZEIT <= @DateMax )
GROUP  BY Pilots.NAME,
          Models.DESCRIPTION,
          Flights.KURSLAENGE * 4828 * Flights.DREIECKE + Flights.SPEED,
          Flights.MODEL_ID,
          Flights.SPEED,
          Flights.DREIECKE * Flights.KURSLAENGE * 0.0048284,
          Flights.FLIGHT_ID,
          Pilots.PILOT_ID,
          Flights.STARTZEIT,
          Flights.DREIECKE,
          Flights.CATEGORY_ID,
          Pilots.VORNAME,
          Flights.KURSLAENGE,
          Flights.PLACE_ID
HAVING ( Flights.CATEGORY_ID = @CatId )
       AND ( Flights.STARTZEIT >= @DateMin )
ORDER  BY POINTS DESC 

现在我收到了错误：

  如果SELECT DISTINCT为，则

ORDER BY项必须出现在选择列表中   指定的

将'ORDER BY POINTS DESC'替换为例如'ORDER BY Flights.SPEED DESC'也可以。

上述陈述不再起作用的原因是什么？