SQL排序和选择一个最接近的值

Question

我有多个表并连接每个表。结果是这样的：

 CarId CarLat CarLon Path Minute Distance 
     325 36.000 37.200 H4  74  250 
     344 36.050 37.040 H6  75  500 
     365 36.300 37.600 H4  76  750 
     311 36.060 37.080 H5  77  800 

正如你所看到的，路径有2个H4，我想要显示更小的分钟路径。像这样：

 CarId CarLat CarLon Path Minute Distance 
     325 36.000 37.200 H4  74  250 
     344 36.050 37.040 H6  75  500 
     311 36.060 37.080 H5  77  800 

我该怎么做？

Answer 1

您可以使用SQL SERVER ROW_NUMBER来确定这一点。

因此，像

;WITH Vals AS (
     SELECT *, 
       ROW_NUMBER() (PARTITION BY Path ORDER BY Minute) RowID 
     FROM Table 
) 
SELECT * 
FROM Vals 
WHERE RowID = 1 

Answer 2

MIN分钟和GROUP BY

SELECT CarId, CarLat, CarLon, Path, MIN(Minute), Distance 
FROM table 
GROUP BY CarId, CarLat, CarLon, Path, Distance