在指定时间段分组求和
SELECT t.StationNo, ROUND(SUM (t.RainHour),1) RainHour FROM MET_AutoStationHourMessage_copy t WHERE t.StationNo = '54263' AND (t.DataTime BETWEEN DATEADD(HOUR, -24, '2018-01-15 00:00:00') AND '2018-01-15 00:00:00') GROUP BY t.StationNo