Question

SQL Server中有一个查询：

SELECT  
    Segment_ID = Segment_ID.Segment_ID,
    GEOMETRY::STGeomFromText(Track.Track.STAsText(),4326) as the_geom,
    a.NumAll,
    a.AverageDailyIntens,
    a.AverageDailyIntensCar,
    a.Loading   
FROM dbo.Segment_ID
RIGHT JOIN Road  ON Segment_ID.Road_ID = Road.Road_ID
LEFT JOIN Track ON Segment_ID.Segment_ID = Track.Segment_ID
outer apply (select top 1 Intensity.NumAll,Intensity.AverageDailyIntens,Intensity.AverageDailyIntensCar,Intensity.Loading   
from Intensity 
         where Segment_ID.Segment_ID = Intensity.Segment_ID
         ORDER BY Intensity.NumAll) a

它工作正常，但不是我想要的。它给了我Intensity Segment_ID.Segment_ID = Intensity.Segment_ID的第一行，但我想要获取最新一行。

在表格Intensity中，我的日期列的日期类似于此2009-02-20 15:00:00.000 如何使用最新日期对Segment_ID行进行排序？

Answer 1

尝试更改ORDER BY子句，按日期列降序排序：

outer apply (
   select top 1
          Intensity.NumAll
        , Intensity.AverageDailyIntens
        , Intensity.AverageDailyIntensCar
        , Intensity.Loading   
   from Intensity 
   where  Segment_ID.Segment_ID = Intensity.Segment_ID
   ORDER BY Intensity.your_date_field DESC
   ) a

如何从表中选择一个新行？

1 个答案: